ANNIVERSARY ADDRESS OF THE PRESIDENT. 53 



In a paper read here on 27th of June, 1870, descriptive of a large 

 series of remains which, by their close association, were thought by 

 Mr. Mansel-Pleydell, under whose personal supervision they were 

 exhumed, to form one skeleton, that of a long-necked Plesiosauroid 

 (P. Manseli, Hulke), attention was drawn by the author to the close 

 resemblance of the humerus of this saurian to the type specimen in 

 the British Museum labelled " No. 31,975. Femur, Plesiosaurus 

 (later Pliosaurus) trochanteric, Owen," their similarity being so 

 great as to favour tbeir generic and perhaps specific identity. The 

 striking resemblance of the femur also of Plesiosaurus Manseli to the 

 type fossil in the British Museum labelled "No. 31,787, a femur of 

 Pliosaurus brachydeirus" was also noticed. The presence of a third 

 bone in the second segment of the limb was demonstrated in Plesio- 

 saurus Manseli (fig. 7), and shown not to be peculiar to Pliosaurus 

 (P. portlandicus). It should be remembered that the paddle of Plesio- 

 saurus Manseli was identified as such by its association with other 

 parts of the skeleton, which was indubitably that of a long, slender- 

 necked Plesiosauroid ; whilst the paddle of Pliosaurus portlandieus, 

 bought of a dealer (Mr. Smith of Weymouth), had been obtained by 

 him from quarrymen, and it was not found with other remains, 

 such as the teeth or cervical vertebrae ascribed to Pliosaurus. Later 

 the British Museum obtained from the same dealer some trunk- 

 vertebrae which may have come from the same spot where the paddle 

 was found ; but there is nothing decisive of this, and trunk-vertebrae 

 have not the same typical value as cervical. 



Prom this I think it will be apparent that proof is yet wanting 

 that the form of paddle ascribed to Pliosaurus is really Pliosaurian ; 

 whilst there is evidence that such paddles were actually possessed 

 by Plesiosaurus Manseli. 



A very interesting question, and one having a much wider mor- 

 phological bearing than in relation to Sauropterygia, is the homology 

 of the third bone in the epipodial segment of the paddle *. This 

 (marked No. 67'. figs. 1, 2, pi. iv., in his memoir on Pliosaurus port- 

 landicus) Prof. Owen regards as the homologue of the fabella present 

 in some Plesiosauri (P. rugosus), " where (he says) its homotype 

 in the fore limb is represented by a detached olecranon process of 

 the ulna." The first two ossicles in the figure of the Portland paddle 

 referred to, counted from the tibial (or radial) border, are numbered 

 by Prof. Owen 66, 67, the numbers by which he always denotes the 

 tibia and fibula ; and he continues, " whether to regard the ossicle 

 marked 67' as the apophysial lever of the fibula or as the calcaneum 

 may be a question. The ossicle marked 67', in the Portland paddle 



* Recent investigators, amongst whom I must particularly mention Gegenbaur, 

 have shown that the carpus or tarsus (mesopodium, Marsh) of all Vertebrata is 

 constructed upon a common plan, however greatly this may be hidden under 

 external diversities of form, and that it consists of a proximal row of three bones, 

 of which two are named respectively, from their relation to the bones of the 

 forearm and leg (or the epipodium), os radiale, os ulnare, os tibiale, os fibulare ; 

 of an intermediate ossicle, os intermedium ; of a distal row of ossicles in number 

 corresponding to the digits ; and, lastly, of one or two ossicles placed centrally 

 between the proximal and distal rows, ossa centralia. 



VOL. xxxix. e 



