1909-10.] Morphology of the Manus in Platanista gangetica. 511 
mediate joint (figs. 4, 5). The epiphyses of the bones of the fore arm, meta- 
carpus and phalanges were fused with their respective shafts. In the two 
younger animals the carpal ossific nodules were imbedded in cartilage often 
of some thickness, so that the bony nodules did not directly articulate 
with each other. No appearance of ossifying epiphyses could he seen in 
connection with the bones of the fore arm, the metacarpus and the phalanges, 
but the proximal epiphysis of the humerus was ossified but not fused with 
its shaft. 
The intermedium, the largest bone in the carpus, was present in all my 
specimens, and measured in one adult 30 by 26 mm. It was opposite the 
interosseous interval in the fore arm, and had a large articulation both with 
radius and ulna, less so with radiale, carpale 2, carpale 3, and with a bone 
which I regard as an os centrale. The ulnare was not present as a separate 
bone in any specimen. Owing to variations in the carpus at the radial 
margin the bones in that region required special attention. As a rule an 
elongated bone, 30 mm. by 13 mm. in one adult, lay close to this margin, which 
articulated proximally with the radius and distally with the metacarpal of 
the pollex (fig. 4). It was marked by a notch at its ulnar border, which 
indicated that it represented two bones, the radiale being the proximal and 
carpale 1 the distal element ; it will be convenient to name the conjoined 
bone radiale-carpale (fig. 1, scheme 2). In the right carpus of one specimen, 
however, the radiale and carpale 1 were distinct bones, separated from each 
other by intervening cartilage, and this condition not only enabled me to 
determine the correct interpretation of the conjoined nature of the radiale- 
carpale bone (fig. 2, scheme 1), but also decided the question of the presence 
of an os centrale. 
Variations existed in the number of the distal carpalia. In the right 
carpus above referred to carpale 1 was a separate bone and articulated with 
M i, radiale, carpale 2 and the os centrale. In all the specimens carpale 2 and 
carpale 3 were separate bones, carpale 2 articulating with and belonging to 
M ii ; carpale 3 to M iii. On the ulnar side of carpale 3 was a distal carpal, 
usually the largest bone in the distal row, measuring in one adult 20 by 
21 mm. : it articulated by its disto-ulnar border almost equally with M iv 
and M v, by its proximal border with the ulna and by the radial border with 
carpale 3. By articulating approximately in equal proportions with M iv 
and M v it probably represented carpale 4 and carpale 5 fused together at an 
early stage of development, though it is possible that carpale 5 might not 
have been differentiated even as a cartilage, and that carpale 4 had grown 
laterally to provide a carpal articulation for M v. As the ulnare did not 
exist as a separate bone it may perhaps be represented potentially in the 
