xiT INTRODUCTION. 



to those of the plains of India, -^-here only stragglers are to be occasionally found and then rarely far 

 from the base of these mountain ranges. The Schizothoracinj: or Hill barbels are carps more or less 

 covered with minute scales or destitute of any. They have a membranous sac or slit anterior to the anal 

 tin, which is laterally bounded by a row of vertically placed scales, like eave-tiles, and which are 

 continued along the base of the anal fin. They are conhned to cold regions or at least to localities 

 possessing snow -fed rivers, many of which rivers end in lakes and do not go to the sea. They extend 

 from Eastern Afghanistan and Western Turkestan through Tibet and the most westerly districts of 

 China. One of the Genera (Oreitms) having a sucker behind the lower lip is able to exist in the rivers 

 of the sub-Himalayan range. Here then is a group of fish which has not spread to the alluvial plains 

 of India from the Himalayas, they being evidently residents of cold climates. 



Burmese and Siamese sub-region. — Of this it is merely the Western portion or that of Burma that claims 

 our attention. In it we find 63 Genera of fresh-water fish recorded : 4 are found in it and in the 

 Ceylonese, but not in the Hindustan sub-region, 5 are restricted to Burma : and .54 are common to it 

 and to the Hindustan sub-region : out of the 63 Genera 41 extend to the Malay Archipelago. But it 

 must not be overlooked that I have included Assam in the sub-region of Hindustan, and for the following 

 reason, owing to the Brahmaputra river entering the Gangetic system, an easy mems exists for enabling fishes 

 to belong to both deltas, in fact very many forms appear to be found in the three large watersheds of the 

 Brahmaputra, Ganges and Indus. Similarly we find the fish-eating crocodile Gavialis Ganiieticus 

 common to all, but not extended to the Ceylonese sub-region nor to Burma. 



Omitting for the present from whence the type forms of vertebrate life were derived, we require 

 to know how it is that some of the identical species of fish are found along the Western ghauts of India 

 and in the Himalayas, but absent from the sub-region of Hindustan ? and how is it we see some genera 

 identical in Ceylon and in the Malay Archipelago or in China, but absent from India and Burma ? 



The presence of certain Chinese, Malayan, Burmese and Siamese foi-ms in Ceylon and in the 

 Western ghauts, with their absence from the intervening alluvial plains of Hindustan, leads to the 

 supposition already touched npon that, at an antecedent date some connection existed between these earlier 

 geological formations and the more eastern countries. We observe some identical forms in the island 

 of Ceylon and in Java or China, but absent from intervening localities : but does this prove more than 

 that some of those intervening stations have passed away, having been perhaps submerged in the Indian 

 Ocean ? Between Ceylon and the islands of the Malay Archipelago are the Nicobars, not far removed 

 are the Andamans. I have examined some fresh-water fishes (Nuria) from the Nicobars, from 

 ■whence they were brought by Mr. Ball, and find them identical with the species existing in India and 

 Burma. I have personally examined some streams at the Andamans, from which I obtained Ophiocephalus 

 gaclma and Haplochilus panchax, both common to the mainland, and these would seem to point out that 

 a land connection may have existed between these islands and Burma, perhap)S being also extended to 

 Ceylon and the Malabar coast. 



If this was the route by which fish obtained access from Malaysia to Ceylon, may they not in like 

 manner have been diffused along the hills of Siam and Burma to the Himalayas ? and this would account 

 for such forms as Siliirus, common to these three regions, to the two species of Homalupfera. existing in 

 the Western ghauts and also on the Himalayas. And when we find that the Genera Sihirus, Exostoma, 

 and to a great extent Oreinus are still found thriving along the whole extent of the Himalayas from 

 Afghanistan on one hand to China or even Siam on the other, we perceive that such a view is not 

 contrary to present existing facts. 



In the alluvial plains of Hindustan there appear to be traces of two piscifaunas, one from the 

 North conjoined with the Ethiopian, and one from the East obtained again from ^lalaysia by way of 

 Burma and Assam. Whether these plains at one period had a wholly Malayan fauna as some suppose I 

 shall not discuss, the late Dr. Stoliczka considered that such was the case, but it became more or less 

 destroyed in those parts which were afiected by the enormous volcanic eruptions, characterized as the 

 trap formation of Central and North-West India. It was after this time that he supposed the 

 African element obtained access to the Hindustan sub-region, and it may have been so, but as already 

 shown it entered (if we take fish as our guide) by way of the Mediterraneo-Persic sub-region, and we 

 still find genera of the latter region (not found in Africa) along the Western ghauts of India {ScajjJdodon) 

 and also at the base of the Himalayas (Eughjiitosternum). 



Whether this element never extended to any considerable extent to Eastern Bengal or whether the 

 Burmese forms subsequently obtained a preponderance there, or whether as seen in Discognathus lamta, 

 it is still spreading, are problems requiring .solution, but it is quite certain that at the present time the 

 Malayan element is in the majority in the plains of Hindustan, due perhaps to a second wave of fish-life 

 received from the East. 



Space prevents my entering upon the question from whence these types of genera have originally 

 been derived ? Are they all or only some of Pala?arctic origin ? Have modifications occurred in fish as 

 they have neared the Tropics, by which we could account for all the various families and genera which 

 we now perceive ? 



I would first remark that Acanthoptertgiax or spiny-rayed forms of fresh-water fishes in India 

 are most numerous in maritime districts, next in the deltas of large rivers, while they decrease as we 

 proceed far inland. The CrPEixiD^ and SiLnRiDj; are the chief elemeuts of the Indian fresh-water 



