of an almost perfect Skeleton of the Plesiosaurus. 415 



though thenumber of the cervical vertebree is thus unexampled, 

 yet the length of the neck is nearly rivalled by another of the 

 reptile class, namely, the land tortoise. The length is in this 

 case concealed by the anterior extension of the shell ; the neck, 

 however, notwithstanding its elongation, has only eight verte- 

 brae. The general proportions of the tortoise, its length of 

 neck, shortness of tail, and the smallness of its head, are in 

 some degree analogous to what we observe in the Plesiosaurus ; 

 but the structure of the head and teeth of the latter, and its 

 want of shell, entirely negative the idea of its being intimately 

 allied to the tortoise, and decidedly connect it with the Saurian 

 order. 



It will be necessary to subjoin a few words on the inferior 

 hatchet-shaped processes which may be seen depending on 

 either side from the lower part of the cervical vertebrae. Most 

 animals present traces of these processes ; they are particularly 

 prominent in many of the long-necked quadrupeds, and in 

 birds project into a long styloid branch ; a rudiment of these 

 may be observed in man, but I am not aware that any parti- 

 cular name has been assigned to them*. They have been 

 sometimes confounded with the transverse processes, to which 

 they often form a wing-like appendage. These processes are 

 important, as serving to determine the number of the cervical 

 vertebrae, and as affording very close analogies between the 

 Plesiosaurus and the crocodile ; in both these animals these in- 

 ferior hatchet-shaped processes are exactly similar in figure, 

 and form separate pieces attached to the body of the vertebrae 

 by a double stem. In the figures given of the cervical verte- 

 brae in my former memoir, this stem alone, and the double su- 

 ture which receives it, could, from the imperfect state of the 

 specimens, be represented ; but I then expressed my convic- 

 tion that the structure resembled that of the same part in the 

 crocodile, and my conjecture is now verified. 



The thirtj'-five anterior vertebrae of the Plesiosaurus exhibit 

 these processes distinctly characterized, and are therefore 

 beyond all doubt cervical ; in the six following the processes 

 become lengthened, and gradually lose their natchet-shaped 

 extremity, assuming rather the form of false ribs, and should 

 therefore perhaps be classed as anterior dorsal ; but the whole 

 forty-one are clearly placed before the pectoral extremities. 

 In the crocodile there are seven cervical vertebrae with hatchet- 



• Dr. Macartney, in his Anaton)y of Birds, says, " The transverse pro- 

 cesises of the vertchra" of the niiiUlIc of the neck spread forwards, and send 

 down n styloid process of some lcn;,'th."^ — " The anterior styloid processes 

 are hut little observable in the rapacious and passerine tribes, the [larrot, 

 &c. ; but they are very marked in the lonp-nccked birds." 



.shaped 



