92 T. KOMAT : STUDIES ON TWO ABERRANT CTENOPHORES 



DIAGNOSIS OF ALL KNOWN SPECIES OF PLATYCTENEA. 



Order Platyctenea, Bourne ('oo). 

 Family Gastrodidae nov. 

 Genus Gastrodes. Korotneff ('88) 

 Parasitic in Salpa; disc-like, but more or less concave on ventral 

 side; colourless; comb-plates present only in large individuals; meridional 

 canals broad especially in small individuals, showing little sign of 

 branching; tentacles rudimentary; eggs scattered in ventral epidermis, 

 sperms unknown, i species : 



Gastrodes parasitiaim Korotneff ('88). 

 Size : up to 3 mm. Locality : Nizza, Misaki. 

 Family Ctenoplanidae Willey ('96). 

 Genus Ctenoplana Willey ('96). 

 Both swimming and creeping; body more or less cap-like, brightly 

 coloured; comb-plates present; tentacles with numerous branches; meri- 

 dional canals represented by four interradially situated broad pouches, 

 with richly anastomosing branch canals. Sperms developing in compact 

 masses [)n>vided with sperm-ducts, eggs unknown. 3 species: 

 Ctenoplana koivalevskii Korotneff ('88).* 

 Colour crimson; body in swimming attitude shaped like a truncate 

 pyramid; median dorsal surface concave; free margin of skirt frilled. 

 Size: 6 mm. Locality: West coast of Sumatra. 

 C. rosacea Willey ('96). 

 Colour crimson; body in swimming attitude of a quatrilateral 

 form; median dorsal surface convex; free margin of skirt plain. May be 

 a variety of preceding species. Size : 6 mm. Locatity : Eastern Archi- 

 pelago of New Guinea. 



C. korotnejfi Willy ('96). 

 Colour green; body in swimming attitude roof-shaped; median 

 dorsal surface upraised with two upright end-k-noI)s; free margin of skirt 

 slightly frillerl. Size : 6 mm. Locality : Eastern Archipelago of New 

 Guinea. 



Family Tjalfiellidae nov.** 

 Genus Tjalfiella Mortensen ('10). 

 Se.ssile, body laterally comi^ressed, elongate in transverse direction ; 



* Si)ccilic di.iynosis talsin from Wii.li.y (yO, p. .556). 

 ** MoKTKNSKN h.is rcf.rre.l TjalCidla int.. ctrnoplanifhie. lull tlic difforeiicc liclwcen Tjal 

 fiella and Clinoplana is surely '|iiilc siiiricicnt for crectirii; a disliiK t faiiiilv for oncli .if llicin. 



