ANNIVERSARY ADDRESS OF THE PRESIDENT. 55 



the last touch of the femur or propodial element of the limb, and, 

 thrust out of the epipodium, it appears henceforth to belong to the 



Fig. 9. — Hind limb of Sauranodon, Marsh. 



T, the tibia ; i, the intermedium ; F, the fibula ; t, os tibiale ; ./, fibulare 

 c, c, ossa centralia. 



mesopodium, as 0. C. Marsh has remarked in Sauranodon. From 

 this arrangement to such a mesopodium (carpus, tarsus) as that of 

 the living Cryptobranchus japonicus (fig. 13), or of the common land- 

 Salamander (figs. 11, 12), is but a small step. 



Another morphological question upon which the Enaliosaurian 

 paddles throw light is the primitive duality or singleness of the os 

 centrale of the carpus or tarsus (mesopodium), about which opinions 

 differ; for in some extant Amphibia the carpus (tarsus) contains one 

 os centrale, while in others two ossa centralia are present ; and this 

 difference has been occasionally observed in the right and left carpus 

 of the same individual. Now in Sauranodon (fig. 9), Ichthyosaurus 

 (fig. 10), Pliosaurus portlandicus, Owen (fig. 8), and, I believe, also 

 in Plesiosaurus Manseli, the proximal row in the mesopodium (carpus 

 or tarsus) comprises four ossicles, of which, since the two lateral 

 ossicles must by their relations be the os tibiale, os fibulare (os 

 radiale, os ulnare), the two middle cannot be other than two ossa 



