igzi.] vS. L. HoRA : Absence of fins in fishes. 31 



seated characters is linked up with their use or disuse, and that 

 they do not necessarily dwindle away to vanishing point, but may 

 simply drop out of the factorial system." Eigenmann and Cox,' 

 who have recorded the absence of the ventrals in Ameiurus natalis, 

 consider this character as a prepotent variation and suggest that 

 " it is possible that some of the genera of fishes without ventrals 

 have arisen from such prepotent variants^ .... '' Brindley,* who 

 noticed the absence of the ventrals in a specimen of the White 

 Bream {Abramis bltcca, Bloch.) observed "that the defect is con- 

 genital and not the result of accidental injury " Too much 



importance seems to have been attached to the variations in the 

 germ-plasm especially when dealing with such cases of abnor- 

 malities. Dr. N. Annandale suggests, and I agree with him, that 

 such abnormalities may be the result of some injury to the anlagen 

 of the ventral or the pectoral fins in the developing embryo. 

 There is, however, very little material available at present to come 

 to any satisfactory conclusion. 



I will now briefly' deal with the two Indian genera of fresh- 

 water fishes that are distinguished from their nearest relatives by 

 the absence of the ventral lins. These are Channa, Gronov. and 

 Apua, Blyth. The genus Channa, which was hitherto known from 

 Cejdon, the Philippines, China and Japan, has recently been record- 

 ed from Burma by Chaudhuri.^ According to both Giinther* and 

 Day^ this genus is distinguished from Ophiocephaliis, Bloch., by 

 the absence of the ventral fins and the pyloric or coecal appen- 

 dages. In the original description of the genus b}'' Gronovius ' the 

 only significant phrase is " VeMrales nulUe." I have examined 

 two species oi Channa, one descriljed by Chaudhuri {op. cit.) and the 

 other contained in Dr. N. Annandale's Chinese collection. In both 

 these species pyloric appendages similar to those of Ophiocephalus 

 are present. The only character, therefore, that distinguishes 

 Channa from Ophiocephalus is the absence of the ventral fins. The 

 occasional absence of the ventrals has been regarded in other 

 genera as an abnormality or a case of genital variation ; but in 

 Channa this character seems to have become permanent, for large 

 series of specimens with the ventrals absent have been collected 

 from the same localit5^ Moreover, no species of Channa has been 

 described having the same specific characters as any known species 

 of Ophiocephalus. Some people attribute the absence of the ven- 

 trals to the habits of these fishes, but how far this is true I have no 

 evidence to judge at present. 



It is otherwise in the case of the second genus, si pita, which 

 was described from two specimens and has not been recorded since. 

 Vinciguerra" doubted the existence of Apua and referred his spe- 



I Eigenmann and Cox, Amer. Naturalist, XXXV, p. 33 (1901). 



•2 Brindley, Pi-oc. Zool. Sue. London, pp. loS— 109, pi. x (iS'gi). 



8 Chaudhuri, Rec. Ind. Mus. .W'l, p. 284 (1919;. 



+ Gunther, Cat. Brit. Mus. Fishes III, pp. i6S and 4H3. 



>> Day, Fislies of India, II, p. 368. 



'' Catalogue of Fish in the British Museum, p. 99 (1854). 



" N'inciguerra. Ann. Mus. Civ. Star. Nat. Geneva, XXIX, pp. 348-49 1 1889). 



