Subfamily 3. Spongobrachida, Haeckel, 1881, Prodromus, p. 461

Definition.—Spongodiscida with two or more (commonly three or four) spongy radial arms on the margin of the disk, situated in its equatorial plane (with or without a connecting patagium between the arms).

Genus 260. Spongolena, n. gen.

Definition.—Spongodiscida with two opposite spongy arms on the margin of the disk, without a connecting patagium.

The genus Spongolena opens the series of the Spongobrachida, or of the Spongodiscida provided with radial spongy arms on the margin of the disk. Spongolena is the most simple form of this subfamily, and bears only two simple opposite arms, without a connecting patagium. It corresponds to Amphibrachium (Porodiscida) and to Diplactura (Coccodiscida). Also there is no patagium. Spongolena may easily be confounded with Spongurus (compare my Prodromus, 1881, p. 461); but in the true Spongurus (an ellipsoid) the transverse section is circular, in Spongolena elliptical.

1. Spongolena rhopalura, n. sp.

Arms club-shaped, three times as long as broad, at the rounded distal end twice as broad as at the base, and twice as long as the diameter of the circular central disk. Surface nearly smooth.

Dimensions.—Radius of the arms (or the distance from the centre to the distal arm-end) 0.16, distal breadth 0.05, basal breadth 0.03.

Habitat.—Pacific, central area, Station 273, depth 2350 fathoms.

2. Spongolena spongura, n. sp.

Arms nearly cylindrical, twice as long as broad, and a little longer than the diameter of the elliptical central disk. Surface thorny, some longer bristle-shaped spines on the distal end of the arms. (Very similar to the ellipsoid Spongurus cylindricus, Monogr. d. Radiol., p. 465, Taf. xxvii. fig. 1, but differs in the compressed lenticular (not ellipsoidal) form of the central disk; the transverse section of the arm is elliptical, not circular.)

Dimensions.—Radius of the arms 0.1, breadth 0.04.

Habitat.—Pacific, central area, Station 270, depth 2925 fathoms.

3. Spongolena cypselura, n. sp.

Arms nearly triangular, not longer than broad, about half as large as the elliptical central disk, at the broader distal end with two very large, widely divergent lateral spines, and between them several smaller, like the tail of a swallow. Surface thorny.

Dimensions.—Radius of the arms 0.2, distal breadth (without spines) 0.15, basal breadth 0.07.

Habitat.—Pacific, central area, Station 272, depth 2600 fathoms.

Genus 261. Spongobrachium, Haeckel, 1881, Prodromus, p. 461.

Definition.—Spongodiscida with two opposite spongy arms on the margin of the disk, connected by a spongy patagium of different texture.

The genus Spongobrachium differs from the foregoing only in the loose spongy patagium, which envelops both opposite spongy arms. It corresponds to Amphymenium among the Porodiscida and to Amphiactura among the Coccodiscida.

1. Spongobrachium ellipticum, Haeckel.

Spongocyclia elliptica, Haeckel, 1862, Monogr. d. Radiol., p. 470, Taf. xxviii. fig. 2.

Spongodiscus ellipticus, Haeckel, 1860, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 844.

Arms nearly square, scarcely as long and broad as the radius of the circular central disk, at the broader distal end truncated. Patagium complete, enveloping the whole disk with the arms, and forming a larger elliptical disk of looser framework. (In my Monograph, 1862, loc. cit., I had not distinguished the opposite darker arms, opposite in the longer axis of the elliptical disk, from the enveloping looser framework of the patagium. In larger specimens of the Challenger collection this distinction is very evident.)

Dimensions.—Radius of the arms 0.12, breadth 0.05; major axis of the elliptical patagium 0.24, minor 0.16.

Habitat.—Cosmopolitan; Mediterranean, Atlantic, Pacific, surface.

2. Spongobrachium lanceolatum, n. sp.

Arms club-shaped, twice as long as broad, at the distal end pointed, five times as long as the radius of the circular central disk. Patagium complete, enveloping the whole disk with the arms, and forming a larger lanceolate disk of looser framework. (Similar in form to Amphymenium pupula, Pl. , fig. 8, but with an irregular spongy framework and pointed ends.)

Dimensions.—Radius of the arms 0.16, breadth 0.05; major axis of the lanceolate patagium 0.32, minor axis 0.12.

Habitat.—Pacific, central area, Station 270, surface.

Genus 262. Rhopalodictyum, Ehrenberg, 1860, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 830.

Definition.—Spongodiscida with three spongy arms on the margin of the circular or triangular disk, without a connecting patagium.

The genus Rhopalodictyum comprises those very common forms of Spongodiscida in which the margin of the disk is provided with three simple, free, spongy arms. It corresponds to Dictyastrum and Rhopalastrum among the Porodiscida, to Trigonactura among the Coccodiscida. The typical species of this genus is Rhopalodictyum abyssorum of Ehrenberg, the only species figured by him. His diagnosis of the genus was very insufficient, and agreed with that of his Dictyastrum (compare above the improved diagnosis of this genus, p. , and my Monograph, p. 466).

Subgenus 1. Rhopalodictya, Haeckel.

Definition.—Triangular shell regular, with three arms of equal size and equidistant.

1. Rhopalodictyum abyssorum, Ehrenberg.

Rhopalodictyum abyssorum, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 299, Taf. viii. fig. 17.

Arms of equal size and equidistant, club-shaped, about as long as the diameter of the triangular central disk, and a little longer than the breadth of the pear-shaped rounded distal end. Surface rough.

Dimensions.—Radius of the arms 0.11, basal breadth 0.03, distal breadth 0.06.

Habitat.—Cosmopolitan; Atlantic, Indian, Pacific; tropical zone, surface.

2. Rhopalodictyum truncatum, Ehrenberg.

Rhopalodictyum truncatum, Ehrenberg, 1861, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 301.

? Dictyastrum angulatum, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 289, Taf. viii. fig. 18.

Arms of equal size and equidistant, nearly square, with straight edges, towards the truncated end a little broader, about of the same diameter as the central triangular disk. This species is indicated by Ehrenberg only by the short diagnosis, "Radiis stellæ tribus apice truncatis." It is probably identical with his figure of Dictyastrum angulatum (loc. cit.). This latter name I have retained for the similar Porodiscid (above, p. ), mainly because the genera Dictyastrum and Rhopalodictyum, according to the insufficient diagnosis of Ehrenberg, seem to be identical. (Compare my Monograph, 1862, p. 466.)

Dimensions.—Radius of each arm 0.13, basal breadth 0.09, distal breadth 0.1.

Habitat.—Tropical Pacific, Philippine Sea, Station 200, depth 250 fathoms; Atlantic (Mexican Gulf Stream).

3. Rhopalodictyum subacutum, Ehrenberg.

Rhopalodictyum subacutum, Ehrenberg, 1861, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 301.

Arms of equal size and equidistant, club-shaped, three times as long as the diameter of the central disk, which equals the breadth of the thickened distal end; the latter is armed with a strong pyramidal terminal spine. (The diagnosis of Ehrenberg is "Radiis stellæ tribus, apice cuneatis subacutis.")

Dimensions.—Radius of the arms 0.2, basal breadth 0.04, distal breadth 0.07.

Habitat.—North Atlantic, surface and various depths; Greenland; Mexican Gulf Stream; Færöe Channel (John Murray).

4. Rhopalodictyum bifidum, n. sp.

Arms of equal size and equidistant, in the distal half forked, twice as long as the diameter of the central disk; both fork branches half as broad as the simple basal part, truncated at the distal end.

Dimensions.—Radius of the arms 0.16, basal breadth 0.08, distal breadth 0.04.

Habitat.—North Pacific, Station 237, surface.

Subgenus 2. Triactinosphæra, Dunikowski, 1882, Denkschr. d. k. Akad. d.

Definition.—Triangular shell bilateral or irregular, with three arms of different size or distance.

5. Rhopalodictyum zittelii, Haeckel.

Triactinosphæra zittelii, Dunikowski, 1882, Denkschr. d. k. Akad. d. Wiss, Wien, vol. 45, ii. p. 192.

Arms of different size and at unequal distances, one odd arm being a little shorter than the two paired arms; the odd angle between the latter is larger than the paired angles between them and the former. Arms club-shaped, their basal semi-cylindrical, half as broad as the spherical distal half, which bears a strong, conical, terminal spine. The discoverer of this remarkable, very old, Liassic species, Dunikowski, supposes that it is not a true Discoid, from the absence of a central disk; in my opinion the central disk (nearly spherical) has the same relation to the arms as in many other Discoidea, their equatorial plane is the same.

Dimensions.—Radius of the odd arm 0.18, of the paired arms 0.24; basal breadth 0.08, distal breadth 0.16.

Habitat.—Fossil in the Alpine Lias, Schafberg, near Salzburg, Dunikowski.

6. Rhopalodictyum elongatum, n. sp.

Arms of different size and at unequal distances, one odd arm being twice as long as both paired arms; the odd angle between the latter much larger than both equal paired angles. Arms nearly cylindrical, little flattened, three to six times as long as broad, with rounded blunt distal end.

Dimensions.—Radius of the arms 0.15 to 0.3, breadth 0.05.

Habitat.—Pacific, central area, Station 274, surface.

7. Rhopalodictyum curvatum, n. sp.

Arms of different size and at unequal distances, irregular, more or less curved, nearly cylindrical, five to ten times as long as broad, with rounded blunt distal end. (There were observed only two specimens of this remarkable irregular species; in one specimen all three arms were simple, in the other one odd arm forked. The length of the arms and the size of the angles between them seems to be very different and variable.)

Dimensions.—Radius of the arms 0.3 to 0.6 to 1.15, breadth 0.06 to 0.12.

Habitat.—Pacific, central area, Station 271, surface.

Genus 263. Dictyocoryne, Ehrenberg, 1860, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 830.

Definition.—Spongodiscida with three spongy arms on the margin of the circular or triangular disk, connected by a spongy patagium of different texture.

The genus Dictyocoryne differs from the foregoing Rhopalodictyum only in the patagium, connecting the three spongy arms, and bears to it the same relation as in the Porodiscida Euchitonia does to Rhopalastrum. The typical species of this genus is Dictyocoryne profunda, the only species figured by Ehrenberg. After his insufficient diagnosis Dictyocoryne was identical with his Spongaster (compare my Monograph, p. 467); but as the type of this latter genus (Spongaster tetras) figured by him, 1872, had four crossed arms, we retain this genus here separate.

Subgenus 1. Dictyocorynula, Haeckel.

Definition.—Triangular shell regular, with three arms of equal size and equal distance.

1. Dictyocoryne profunda, Ehrenberg.

Dictyocoryne profunda, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 307, Taf. vii. fig. 23.

Arms of equal size and equidistant, club-shaped, in the outer circular half three times as broad as in the inner cylindrical half, and much larger than the small triangular central disk. Patagium complete, forming an equilateral triangle with rounded corners.

Dimensions.—Radius of the arms 0.14, basal breadth 0.025, distal breadth 0.07.

Habitat.—Pacific, Philippine Sea, depth 3300 fathoms, Ehrenberg; Station 198, depth 2150 fathoms; Station 274, depth 2750 fathoms.

2. Dictyocoryne tetradiscus, n. sp.

Arms of equal size and equidistant, club-shaped, their outer circular half is quite as large as the circular central disk, and is connected with it by the thin cylindrical inner half, which is scarcely one-fourth as broad. Patagium complete, forming an equilateral triangle with rounded corners and convex sides.

Dimensions.—Radius of the arms 0.16, basal breadth 0.02, distal breadth 0.08.

Habitat.—Pacific, central area, Stations 271 to 274, in 2350 to 2750 fathoms.

3. Dictyocoryne euchitonia, Haeckel.

Dictyocoryne euchitonia, Haeckel, 1862, Monogr. d. Radiol., p. 468.

Arms of equal size and equidistant, lanceolate, twice as long as broad in the distal part, and three times as long as the small circular central disk. Patagium complete, forming an equilateral triangle with pointed corners. (Very similar to Euchitonia köllikeri, Monograph, 1862, p. 511, Taf. xxxi. fig. 6, but quite spongy, not concentric.)

Dimensions.—Radius of the arms 0.15, basal breadth 0.03, distal breadth 0.06.

Habitat.—Mediterranean (Messina), Haeckel.

4. Dictyocoryne trigona, n. sp.

Arms of equal size and equidistant, lanceolate, three times as long as broad in the middle part, and as the diameter of the triangular central disk; their distal end armed with a strong conical radial spine. Patagium complete, forming an equilateral triangle with pointed corners.

Dimensions.—Radius of the arms 0.2, basal breadth 0.02, distal breadth 0.06.

Habitat.—North Atlantic, Canary Islands, surface.

Subgenus 2. Dictyocorynium, Haeckel.

Definition.—Triangular shell bilateral or irregular, with three arms of different sizes or at different distances.

5. Dictyocoryne charybdaea, Haeckel.

Spongocyclia charybdaea, Haeckel, 1862, Monogr. d. Radiol., p. 472, Taf. xxviii. figs. 5, 6.

Spongodiscus charybdaeus, Haeckel, 1860, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 844.

Arms at different distances, nearly equilateral triangular, scarcely half as long as the radius of the large circular central disk. Both paired arms touching at their bases, separated by a great distance from the opposite odd arm. Patagium complete, nearly pentagonal. (The illustration in my Monograph, in the coloured plate xxviii., is better than my description, as I had not exactly separated the arms from the patagium.)

Dimensions.—Radius of the arms 0.18, basal breadth 0.08.

Habitat.—Mediterranean (Messina), surface.

6. Dictyocoryne pentagona, Stöhr.

Dictyocoryne pentagona, Stöhr, 1880, Palæontogr., vol. xxvi. p. 118, Taf. vii. fig. 2.

Arms at different distances, club-shaped, little longer than broad at their rounded distal end. Both paired arms smaller and more approximate than the opposite odd arm. Patagium complete, very large, enveloping the whole shell, and forming a pentagon with rectilinear base and transverse constriction, and with five rounded corners.

Dimensions.—Radius of the arms 0.1 to 0.15, middle breadth 0.04.

Habitat.—Fossil in the Tertiary rocks of Sicily, Grotte, Stöhr.

7. Dictyocoryne agrigentina, Stöhr.

Dictyocoryne agrigentina, Stöhr, 1880, Palæontogr., vol. xxvi. p. 118, Taf. vii. fig. 1.

Arms at different distances, club-shaped, about twice as long as broad, and smaller than the large triangular central disk. Both paired arms smaller and more approximate than the opposite odd arm. Patagium incomplete, enveloping only the basal half of the arms as a circular spongy disk of loose framework.

Dimensions.—Radius of the arms 0.18, basal breadth 0.05, distal breadth 0.08.

Habitat.—Fossil in the Tertiary rocks of Sicily, Grotte, Stöhr.

8. Dictyocoryne echinata, n. sp.

Arms unequal and at different distances, club-shaped, in the distal half twice as broad as in the basal half, three times as long as the small triangular central disk, at their distal end armed with one larger and several smaller conical spines. Both paired arms with touching bases, and only half as large as the doubly remote odd arm. Patagium incomplete, enveloping only the basal half of the arms, and forming a circular disk of looser framework. Surface thorny.

Dimensions.—Radius of the arms 0.15 to 0.2, basal breadth 0.03, distal breadth 0.06.

Habitat.—South Atlantic, Station 325, surface.

Genus 264. Spongasteriscus, Haeckel, 1862, Monogr. d. Radiol., p. 474 (sensu restricto).

Definition.—Spongodiscida with four spongy arms on the margin of the circular or quadrangular disk, crossed in two equatorial diameters, without a connecting patagium.

The genus Spongasteriscus (in the restricted definition here stated) exhibits on the margin of the disk four spongy arms, which form either a regular or a bilateral cross. It corresponds to Stauralastrum and Myelastrum among the Porodiscida, to Astractura among the Coccodiscida.

Subgenus 1. Spongasteriscinus, Haeckel.

Definition.—Cross formed by the four arms regular, rectangular, with equal-sized and equidistant arms.

1. Spongasteriscus ovatus, n. sp.

Arms at equal distances, forming a regular, rectangular cross, egg-shaped, with a broader rounded distal end, one and a third times as long as broad, and three times as long as the radius of the central disk; in the latter three to four concentric rings.

Dimensions.—Radius of the arms 0.1, greatest breadth 0.06.

Habitat.—Western Tropical Pacific, Station 225.

2. Spongasteriscus clavatus, n. sp.

Arms at equal distances, forming a regular, rectangular cross, club-shaped, about as long as the diameter of the central disk, and at their rounded distal end one and a third times as long as broad, at their narrow base only one third as broad. In the centre five to six concentric rings.

Dimensions.—Radius of the arms 0.13, distal breadth 0.06, basal breadth 0.02.

Habitat.—Pacific, central area. Station 271, surface.

3. Spongasteriscus mucronatus, n. sp.

Arms at equal distances, forming a regular, rectangular cross, club-shaped, three times as long as the radius of the central disk, in the distal half nearly circular, three to four times as broad as at the narrow base. The rounded distal end armed with a strong pyramidal spine. In the centre no concentric rings. (Similar to Stauralastrum rhopalophorum, Pl. , fig. 1, but quite spongy.)

Dimensions.—Radius of the arms 0.12, basal breadth 0.03, distal breadth 0.02.

Habitat.—Pacific, central area, Station 265, depth 2900 fathoms.

4. Spongasteriscus furcatus, n. sp.

Arms at equal distances, forming a regular, rectangular cross, in the distal third forked; both fork branches half as long as the basal undivided part of the arm, which is twice as long as broad. Distal ends of the eight branches blunt, rounded. In the central disk no concentric rings.

Dimensions.—Radius of the arms 0.12, basal breadth 0.03; distal breadth of the branches 0.02.

Habitat.—North Pacific, Station 244, depth 2900 fathoms.

5. Spongasteriscus armatus, n. sp.

Arms at equal distances, forming a rectangular, regular cross, in the distal half forked; both fork branches of the same length as the basal undivided part of the arm, which is nearly square. Distal ends of the eight branches armed with a strong pyramidal spine. In the central disk no concentric rings. (Similar to Dicranastrum cornutum, Pl. , fig. 2, but quite spongy.)

Dimensions.—Radius of the arms 0.18, basal breadth 0.03, distal breadth 0.015.

Habitat.—South Pacific, Station 295, depth 1500 fathoms.

Subgenus 2. Spongasterisculus, Haeckel.

Definition.—Cross formed by the four arms, bilateral or irregular, with the arms at different distances.

6. Spongasteriscus quadricornis, Haeckel.

Spongasteriscus quadricornis, Haeckel, 1862, Monogr. d. Radiol., p. 474, Taf. xxviii. figs. 8-10.

Spongodiscus quadricornis, Haeckel, 1860, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 844.

Arms at different distances, forming a bilateral or irregular cross, grouped in two opposite pairs; their form equilateral triangular; their length smaller than the radius of the large circular central disk, which exhibits in the interior eight to sixteen concentric rings.

Dimensions.—Radius of the arms 0.2, of the central disk 0.13; basal breadth of the arms 0.08.

Habitat.—Mediterranean (Messina), Haeckel, surface.

7. Spongasteriscus tetraceros, Haeckel.

Spongasteriscus tetraceros, Haeckel, 1862, Monogr. d. Radiol., p. 475.

Arms at different distances, forming a bilateral or irregular cross, grouped in two opposite pairs; their form isosceles triangular; their length larger than the radius of the large elliptical central disk, which exhibits in the interior six to twelve concentric rings.

Dimensions.—Radius of the arms 0.16, of the central disk 0.1; basal breadth of the arms 0.06.

Habitat.—Mediterranean (Messina), North Atlantic (Canary Islands), surface.

8. Spongasteriscus myelastrum, n. sp.

Arms at different distances, forming a bilateral or irregular cross, grouped in two opposite pairs; the arms of one pair broader and shorter than the arms of the other pair. Each arm in its basal half simple, in the distal half forked; ends of the fork branches blunt. In the central disk no concentric rings. (Similar to Myelastrum octocorne, Pl. , fig. 12, but quite spongy.)

Dimensions.—Radius of the arms 0.2, basal breadth 0.05, distal breadth 0.02.

Habitat.—North Pacific, Station 236, surface.

Genus 265. Spongaster, Ehrenberg, 1860, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 833.

Definition.—Spongodiscida with four spongy arms on the margin of the circular or quadrangular disk, connected by a spongy patagium of different texture.

The genus Spongaster differs from the foregoing Spongasteriscus in the patagium connecting the spongy arms, and bears therefore to it the same relation as, in the Porodiscida, Histiastrum does to Stauralastrum, or, in the Coccodiscida, Stauractura does to Astractura. The typical specimen, figured by Ehrenberg (Spongaster tetras), exhibits a regular, square disk, as also some other species. In a certain number of other species (formerly united by me with Spongocyclia) the quadrangular disk is bilateral.

Subgenus 1. Spongastrella, Haeckel.

Definition.—Cross formed by the four arms regular, rectangular, with the arms of equal size and equidistant.

1. Spongaster tetras, Ehrenberg.

Spongaster tetras, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 299, Taf. vi. (iii.) fig. 8.

Dictyocoryne tetras, Haeckel, 1862, Monogr. d. Radiol., p. 469.

Arms at equal distances, forming a rectangular, regular Myelastrum, papiliocross, club-shaped, about twice as long as the diameter of the square central disk and eight times as long as broad at their base. Distal ends rounded, perfectly enclosed by the complete patagium, which forms a regular square, with slightly concave sides.

Dimensions.—Radius of the arms 0.12, distal breadth 0.03, basal breadth 0.015; length of the square side 0.2.

Habitat.—Cosmopolitan; Atlantic, Indian, Pacific, surface and in various depths.

2. Spongaster quadratus, n. sp.

Arms at equal distances, forming a regular, rectangular cross, club-shaped, about four times as long as the diameter of the central circular disk, and five times as long as broad at the base. Basal third of the arms square; distal two thirds triangular, three times as broad, with a truncated distal end. Patagium complete, perfectly enveloping the arms, and bordered by an elegant, radially striated, broad edge, forming a regular square. (Similar to Histiastrum quadratum, Pl. , fig. 4, but quite spongy.)

Dimensions.—Radius of the arms 0.15, distal breadth 0.06, basal breadth 0.02; length of the square side 0.25.

Habitat.—Pacific, central area, Stations 270 to 274, depths 2350 to 2925 fathoms.

3. Spongaster cruciatus, n. sp.

Arms at equal distances, forming a rectangular, regular cross, lanceolate, three times as long as broad and as the diameter of the central circular disk. Ends of the arms provided with a short conical spine. Patagium incomplete, enveloping only the basal half of the arms, forming a regular square with concave sides.

Dimensions.—Radius of the arms 0.18, greatest breadth 0.05; length of the square side 0.2.

Habitat.—South Pacific, Station 288, surface.

4. Spongaster pentacyclus, n. sp.

Arms at equal distances, forming a rectangular, regular cross, of the same size and form as the circular central disk, so that the dark interior part of the shell is composed of five equal circular disks, situated in a quincuncial manner. The clearer complete patagium, enveloping the whole cross perfectly, forms a regular square with rounded edges.

Dimensions.—Radius of the arms 0.2; diameter of each of the five circular disks 0.01; length of the square side 0.35.

Habitat.—West Indies, Cuba, surface (Thomson).

Subgenus 2. Spongastromma, Haeckel.

Definition.—Cross formed by the four arms bilateral or irregular, with the arms at different distances.

5. Spongaster orthogonus, Haeckel.

Spongocyclia orthogona, Haeckel, 1862, Monogr. d. Radiol., p. 471, Taf. xxviii. fig. 3.

Spongodiscus orthogonus, Haeckel, 1860, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 844.

Arms at different distances, forming a bilateral cross, grouped in two opposite pairs of equal size and similar form. Arms club-shaped, about as long as the diameter of the central circular disk, enveloped perfectly by the complete patagium, which forms a regular rectangle, the longer side of which is one and a half times as long as the shorter side. (The arms in my figure are not distinctly enough marked.)

Dimensions.—Radius of the arms 0.08, breadth 0.02; length of the larger side of the rectangle 0.15, of the smaller 0.1.

Habitat.—Mediterranean (Messina), surface.

6. Spongaster scyllaeus, Haeckel.

Spongocyclia scyllaea, Haeckel, 1862, Monogr. d. Radiol., p. 471, Taf. xxviii. fig. 4.

Spongodiscus scyllaeus, Haeckel, 1860, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 844.

Arms at different distances, forming a bilateral cross, grouped in two opposite pairs of different size and form, one pair smaller and less divergent than the other. Arms club-shaped, little longer than the radius of the central circular disk, enveloped perfectly by the complete patagium, which forms a trapezium; the convergent longer sides of the latter are one and a half times as long as the larger, and twice as long as the smaller parallel side. (The arms are in my figure, loc. cit., not distinctly enough marked.)

Dimensions.—Radius of the arms 0.12 to 0.14, breadth 0.02; length of both convergent sides 0.24, of the larger parallel side 0.18, of the smaller 0.12.

Habitat.—Pacific, central area, Station 272, surface; Mediterranean (Messina).