OCR Text |
Show 1871.] FRESHWATER SILUROIDS OF INDIA. 715 Head as broad as long, depressed, covered with skin. Snout broad. Caudal peduncle two thirds as high as long. Thoracic adhesive apparatus small. Gill-membranes generic. Lips not fringed. Maxillary barbels with broad bases, and nearly as long as the head, the nasal reaching halfway to the orbit, the external mandibular pair longer than the internal. Occipital process slightly longer than it is broad at its base. Fins. Dorsal nearly as high as the body, its spine half as long as the head and enveloped in skin; adipose dorsal rather low, its base slightly longer than that of the first dorsal. Pectoral spine broad, reaching two thirds of the distance to the base of the ventral, not plaited inferiorly, whilst externally it is smooth, and internally has seven strong denticulations; it is two thirds as long as the head. Caudal forked, lower lobe slightly the longer. Skin smooth. Air-vessel generic. Colours. Uniform brown. Hab. Numerous specimens up to 3 inches long from the upper portion of the Jumna. Geographical distribution.-Throughout India (! Madras), Burmah, to the Malay archipelago. Some species when small appear to be found in mountain-streams. Genus EXOSTOMA, Blyth. Air-vessel in a globular form on either side of the body of the anterior vertebrae, and enclosed in bone. EXOSTOMA BLYTHII, Day, Proc. Zool. Soc. 1869, p. 525. D. ||0. P. ^. V. 6. A.|. C. 13. An erratum occurred in the original description in the number of anal rays, which are seven, the two first of which are undivided. Having been favoured by Mr. Mundali and Dr. Stoliczka with several specimens up to 3 ^ inches in length, I find its habitat to be the rivers below Darjeeling. In some of the larger specimens the caudal fin is not lobed, but its outer rays are rather elongated, whilst all the intermediate ones are of the same length. Geographical distribution.-This genus, so far as I have been enabled to trace its species, commences in the rivers below Darjeeling (E. blythii); it is then found in the Mishnee mountains in Assam (E. labiatum) ; more to the east it has its representatives in Tenasserim (E. berdmorei); whilst specimens were brought by the expedition which went through Upper Burmah to China (E. ander-sonii). The systematic arrangement of the family Siluridce has always been found intricate, judging from the constant changes to which it has been subjected. Although I have no new system to propose, I would draw attention to some points respecting those genera which inhabit the waters of India, which seem to show that further altera- |