SILUKID.E. 
:i'25 
and the ridges rounded ; supraoccipital slightly raised into a median 
prominence in its hinder half ; frontal vacuity not much elongated. 
1’orm. cj- Loo. Lower Pliocene : Siwalik Hills, India. 
16402 b. Type specimen. 
Presented by Col. Sir Proby T. Cautley, K.C.B., 1842. 
Genus HETEROBRANCHUS, Geoffrey St. Hilaire. 
[Savigny, Descript. Egypte, vol. i. 1827, p. 305.] 
As Clarias, hut hinder portion of dorsal fin adipose. 
Surviving in the freshwaters of Africa and the East Indian 
Archipelago. 
Heterobranchus palseindicus, Lydekker. 
1 NS6. Heterobranchus palteindicus , R. Lydekker, Paheont. Indica, 
ser. x. vol. iii. p. 248, pi. xxxvi. fig. 4. 
1 VP e ■ N early complete skull ; British Museum. 
A species probably about 0'4 in length, known only by the skull, 
J 1 h’°h is provisionally ascribed to Heterobranchus on account of 
its close resemblance to the skull of H. intermedins, and also on 
account of the long backward extension of its supraoccipital bone. 
-Not yet precisely definable, but differing from H. intermedins in its 
relatively shorter and wider frontal vacuity and its ethmoid much 
narrowed in front. 
Porm. cj- Loc. Lower Pliocene : Siwalik Hills, India. 
16402 c. Type specimen. 
Presented by Col. Sir Proby T. Cautley, K.C.B., 1842. 
Genus SILURUS, Linnaeus. 
[Syst. Nat. ed. 10, 1758, p. 304.] 
Head not much depressed, the lateral muscles extending some- 
what forwards over the cranial roof, and the whole covered with 
* e soft skin. Gape of mouth extending to beneath the orbit ; 
b e fh very minute, villi form, present on the promaxilla? and dentaries, 
a so on the vomer but not on the palatines. Pectoral fin with 
robust spine, serrated on the posterior or both borders ; pelvic fins 
'rith more than eight rays, arising behind the dorsal fin, which is 
short-based and without anterior spine; no adipose dorsal; anal fin 
™uch extended, almost or completely united with the caudal, which 
18 rou nded. Skin naked. 
The surviving species of this genus inhabit the freshwaters of 
the temperate parts of the Palmarctie Region, some extending even 
t0 north of India. Fragmentary remains of a supposed extinct 
