Apodal Fishes of Bengal. 157 



India by any author. Thus the error of confounding our 

 Indian species with the Synbranchi of Bloch, and JJnibran- 

 chapertura of Lacepede, would appear to have originated 

 in a mistake regarding the locality of one of the species. 



Synbranchus is an Ophicardious genus, having a single lon- 

 gitudial aperture under the throat, several rows of small blunt 

 conical teeth, and a blunt round muzzle without tubulated 

 nostrils. They are said to be furnished with a long narrow 

 natatory air-vessel. Their branchiae are not described fur- 

 ther than that the membrane contains six strong rays. 



11. The remaining genera, with the exception of Alabes, are 

 all composed of species which are foreign to India. Alabes, 

 however, depends upon a small species of the Indian ocean, 

 which differs from Synbranchus in the presence of pectoral 

 fins, American and European genera, appear to be defi- 

 cient in Ophicardious forms, which would seem to be chiefly 

 confined to Africa and Asia. Whether from geographical 

 or other causes, there seems, as far as relates to fishes, a 

 much greater uniformity between India, the coast of Guinea, 

 and the eastern coasts of China to the 30° N. Lat., than with 

 any other corresponding tracts of the same extent. 



12. Synbranchus, Saccopharynx and Alabes are the only 

 genera hitherto known in which we can, a priori, suppose 

 the heart to be situated behind the branchial apertures ; as 

 they have not been examined with a view to this point, it 

 remains to notice briefly the general peculiarities of several 

 Bengal genera, here for the first time brought forward in 

 which this peculiarity is most remarkable. 



First. Pneumbranchus. The intervals between the bran- 

 chial arches are nearly obliterated. The place of pectinated 

 branchial combs is supplied by means of a sack which opens 

 into the mouth over the end of the first arch on either side, 

 the body is cvoered with small imbricated scales, the teeth 

 are placed in two rows, one on the palatines and the other on 

 the maxillaries. 



