INDIAIf TERTIAET & POST-TEETIAET VEETEBEATA. 
TEETIAET EISHES. 
By R. LYDEKKER, B.A., F.G.S., etc. 
(WITH PLATES XXXV [figs. 8-15] TO XXXYII.) 
INTRODUCTORY. 
Siwalik fishes . — Of the literature relating to Siwalik fishes (the description of 
which occupies the greater part of this memoir) there is but little to be said, since a 
paper by M’Clelland, a note by Dr. Gunther, and another by the present writer 
(all of which are quoted in the sequel) constitute almost all that has been hitherto 
written on the subject. 
Compared with those of mammals tlie remains of Siwalik fishes which admit of 
even ordinal determination are extremely rare, although detached vertebrae, fragments 
of fin-spines, etc., are of not uncommon occurrence. The majority of the deter- 
minable remains belong to the families of the Ophiocephalidce and Siluridce, which at 
the present day form such a marked feature in the ichthyic fauna of India ; and it 
is noteworthy that nearly all the specimens of the latter family belong to those 
genera in which the cranial bones are of great relative stoutness, and are covered 
with a characteristic sculpture. Those genera, like Bagrus, in which the cranial 
bones are much thinner, have not left any characteristic remains, although it is 
almost certain that they must have existed in the Siwalik period. The same reason 
will probably account for the almost total absence of the remains of cyprinoids. 
The indications of close affinity between some of the Siwalik siluroids and species 
at present existing in Africa is a circumstance of considerable importance in relation 
to the probable derivation of a great part of the present vertebrate fauna of that 
country from the Oriental region. Of no less interest is the occurrence of 
remains of sharks in the Siwaliks of the Punjab and the Burma, as affording 
, ■ A 
