248—8 INDIAN TERTIARY AND POST-TERTIARY VERTEBRATA. 
Distinctness. — Of the Indian species, C.jagur according to Dr. Day^ has but one 
cranial vacuity ; while C. magur and the allied C. assamensis'^ have not the elevated 
ridge on the supraoccipital, and the skull of G. teysmanni is considerably smaller and 
much flatter. The writer has been unable to identify the fossil with any African 
form of which there are skulls in the British Museum ; and it is certainly distinct 
from the nearly equal-sized C. gariepinus [capensis), in which the cranial vacuities are 
smaller, and the supraoccipital nearly flat. Under these circumstances it is proposed 
to assign the provisional name of Clarias falconeri to the Siwalik species. 
Genus , II. HETEROBRANCHUS, Geoffroy." 
Characters. — This genus is chiefly distinguished from the preceding by the 
structure of the fins ; but the supraoccipital process is more developed, and all the 
species are of small size (pi. XXXVI. fig. 3j. 
Distribution. — Six species are enumerated in Gunther’s “ Catalogue of Fishes,”^ 
of which five are exclusively African, while the sixth is from Banka and Borneo. 
Species. Heterobranchus pal^indicus, n. sp. nobis. 
{From the Siwalihs.') 
History. — The one specimen on which this species is founded was obtained from 
the Siwalik Hills, and belongs to the Cautley collection of the British Museum : it 
has not hitherto been described. 
Skull. — The type specimen is represented of the natural size in plate XXXVI. 
fig. 4 ; a figure of the skull of the existing African H. intermedius being given in 
figure 3 of the same plate. The fossil comprises the nearly complete skull ; the 
chief losses being the premaxillae, the turbinals, the extremity and the lateral wings of 
the ethmoid {eth.). and the extremity of the supraoccipital {sup.). Compared with the 
skull of H. intermedius it will be seen that the resemblance is so close as to leaAm no 
doubt of the generic unity of the two specimens. The fossil and recent skulls are 
of very nearly the same dimensions, and belong to individuals of about fifteen 
inches in length. The fossil differs by the narrower anterior extremity of the 
ethmoid {eth.)., by the shorter and wider frontal vacuity {b), and by the band of 
villiform teeth on the palate being narrower and more extended laterally. The 
united claviculo-coracoidal element of the humeral arch, which is preserved on 
the ventral aspect of the specimen, is also more deeply grooved. In the great 
development of the supraoccipital spine {sup.) the specimen agrees with Heterobran- 
chus, and differs from Clarias. 
Distinctness. — The foregoing comparisons indicate the specific distinctness of the 
Siwalik Heterobranchus from H. intermedius, and therefore probably also from the 
allied H. dorsalis. H. isopterus appears to be distinguished by its inferior size. Of 
the other three species, H. laticeps is not represented in the British Museum collection, 
while there are only young specimens of H. tapeinopterus and H. longifilis, and the 
1 “Fishes of India,” p. 484 (1878). 2 Ibid. p. 485. 
3 “ Desci’ip. Eg. Atl. Poissons,” pi. XVI. fig 2 (1809-13). 4 Volume V pp. 21-23 (1865). 
