Trematoda

Appendix on Trematoda and Nematoda.

BY

J. W. W. STEPHENS, M.D., B.C., D.P.H.

Artyfechinostomum sufrartyfex, Clayton Lane, 1915.—Leiper thinks this may be the same as Echinostoma malayanum, Leiper, 1911, which species Odhner assigns to the genus Euparyphium.

Metagonimus (Yokogawa) yokogawai occurs in dogs in Shanghai. Encysted cercariæ probably in the perch.

Opisthorchis sp.—Skin covered with spines. Gut forks almost reach end of body. Œsophagus two to three times length of pharynx. Ovary multilobed. Ovary and testes in posterior fourth of body. Vitellaria end opposite the ovary. Distinguished from O. felineus by presence of spines and lobed ovary; from O. pseudofelineus and O. noverca by the lobed ovary, and by the fact that the yolk glands do not extend as far as the anterior testis. It agrees with Poirier’s description of O. viverrini in the Indian civet cat, but whether this species has spines on the cuticle is not known.

Habitat.—Man in Chiengmai (Malay States). Fifteen per cent. of prisoners in the jail showed the ova of this species in their fæces.

Schistosome cercariæ.

Schistosome cercariæ belong to the furcocercous division of the Distomata cercariæ.

Distomata cercariæ.

Body without a floating membrane. Tail absent, or if present not cleft to the base. Mouth anterior, gut forked. Oral sucker present. Ventral sucker near middle of body. Eyes generally absent.

Group Fercocercous cercariæ.

Cercariæ single (not in colonies). Tail forked at its end.

Family. Schistosomidæ.

Pharynx absent.

Cercaria bilharzia, Leiper, 1915.

Pigment spots (eyes) anterior to ventral sucker absent, cuticular keel on forks of tail absent.

In Bullinus sp. and Planorbis boissyi in Egypt, (?) in Physopsis africana, South Africa. Adult form, Schistosoma hæmatobium.

Cercaria bilharziella, Leiper, 1915.

Cuticular keel on tail forks present. Pigment spots (eyes) in front of ventral sucker present.

In Planorbis boissyi and P. mareoticus, and in Melania sp. Adult form (?).

For characters of numerous other cercariæ which occur in fresh water molluscs see “Die Susswasserfauna Deutschlands,” Max Lühe, H. 17 (Gustav Fischer, Jena, 1909).

The characters of Cercaria japonica of S. japonicum in the mollusc Katayama nosophora and of C. mansoni have still to be defined.

Schistosoma mansoni, Sambon, 1907.

The evidence appears to be strong that terminal-spined eggs are not found in the West Indies, and that therefore the lateral-spined eggs found in fæces there belong probably to S. mansoni. If this be true, then the egg described by Stephens and Christophers in man in India probably also belongs to another species of Schistosome.