246—6 INDIAN TERTIARY AND POST-TERTIARY VERTEBRATA. 
although one or two species occur in Africa.^ The writer is not aware that any fossil 
forms have been hitherto described. 
Genus. OPHIOCEPHALUS, Block.^ 
Ophiocephalus, sp. a. 
{From the Suvaliks.) 
History . — The first mention of the occurrence of remains of fishes of this family 
in the Siwaliks was made by M’Clelland^ in 1844, on the evidence of the specimens 
noticed below. 
Skulls . — The specimen represented in plate XXXVII. fig. 2 was obtained from 
the Siwalik Hills, and is preserved in the British Museum (Cautley collection). It 
comprises the greater part of the cranium and mandible (the former being crushed 
in behind the orbit) and posteriorly exhibits the pharyngeal teeth (/). The strong 
development of the maxilla, the long series of teeth, the shield-like scales on the 
frontals, the presence of an accessory gill-cavity (as shown by fracture), and the 
general contour, agree so exactly with Ophiocephalus., that there can be no doubt as 
to the genus of the specimen. The large size of the frontal scales shows that the 
specimen belongs to the first group of Dr. Giinther’s^ classification, but beyond this 
the specimen scarcely admits of closer approximation. It agrees in size with the 
head of an adult stuffed specimen of the Indian 0. striatus in the British Museum, 
but appears decidedly less depressed. 
Two other less perfect skulls in the British Museum (Nos. 15374 and 15375) 
from the Siwalik Hills not improbably belong to the same species as the preceding. 
Ophiocephalus, sp. h. 
{From the Siwaliks.) 
Skull. — A much-rolled skull in the British Museum (No. 16402a,) from the 
Siwalik Hills indicates an Ophiocephalus of considerably larger size than the preceding 
specimens, which is not improbably specifically distinct. Owing to the damaged 
condition of the specimen a figure has not been given : the cranial shield-like scales 
are of very large size, and apparently relatively larger than those of the preceding 
species. 
Oeder II. PHYSOSTOMI. 
Family I. SILURIDHJ. 
Characters . — Skin naked or with osseous scutes, but without scales. Barbels 
always present ; maxillae rudimentary, and the margin of the upper jaw formed by 
the premaxillae. 
Distribution . — This extensive family is found in the freshwaters of nearly all 
the temperate and tropical regions, and is very strongly represented in India and 
Africa. The writer is not acquainted with any European fossil representative of the 
1 Giiuther “ study of Fishes,” p 513 (1880). 2 “ Ausliindische Fische.” vol. VITI. p. 137 (1785-95). 
3 ‘ Calcutta Journ. Nat. Hist.’ vol. IV. p. 83 (1844). ^ ” Catalogue of Fishes,’ vol. III. p. 469 (1861). 
