258 CETACEA 
points in common, and do not altogether come under the definition 
either of the Physeteride or the Delphinide, especially in the 
important character of the mode of articulation of the ribs with 
the dorsal vertebra, the tubercular and capitular articulations, 
distinct at the commencement of the series, gradually blending 
together, as they do in most ordinary mammals. The cervical 
vertebree are all free. The lachrymal bone is not distinct from the 
jugal. The jaws are long and narrow, with numerous teeth in 
both. The symphysis of the mandible exceeds half the length of 
the whole ramus. Externally the head is divided from the body 
by a slightly constricted neck. Pectoral limbs broad and truncated. 
Dorsal fin small or obsolete. Fluviatile or estuarine in habits. 
There are three distinct genera, which might almost be made the 
types of families, but it is probably more convenient to keep them 
together, only regarding them as representing three subfamilies. 
Platanista..—Teeth about $9 on each side, set near together, 
rather large, cylindrical, and sharp-pointed in the young; in old 
animals acquiring a large laterally compressed base, which in the 
posterior part of the series becomes irregularly divided into roots. 
As the conical enamel-covered crown wears away, the teeth of the 
young and old animals have a totally different appearance. The 
rostrum and dentigerous portion of the mandible are so narrow 
that the teeth of the two sides are almost in contact. Maxille sup- 
porting very large, incurved, compressed bony crests, which over- 
arch the nares and base of the rostrum, and almost meet in the 
middle line above. Orbits very small and eyes rudimentary, without 
crystalline lens, External respiratory aperture longitudinal, linear. 
Vertebre: C 7, D 10, L 9,C 26; total 52. A small cecum. No 
pelvic bones. Dorsal fin represented by a low ridge. 
One species, P. gangetica, entirely fluviatile, being extensively 
distributed throughout nearly the whole of the river systems, not 
Fic. 88.—Platanista gangetica, (From Anderson.) 
only of the Ganges, but of the Brahmaputra and Indus, ascending 
as high as there is water enough to swim in, but never passing out 
to sea, It is quite blind, and feeds on small fish and crustaceans, 
groping for them with its long snout in the muddy water at the 
bottom of the rivers. It attains the length of 8 feet.2 
1 Wagler, Syst. iphib. ete., p. 85 (1830). 
* The anatomy of Platanista is fully described by J. Anderson, Zoological 
Results of Two Expeditions to Western Yunnan, 1878. 
