122 The Rev. W. D. Conybeare's Additional Nolices 



data are sufficient to render this restoration a very close approximation but 

 the sutures between the bones, being- in many instances doubtful, are indicated 

 only by dotted lines. 



On the whole, then, the manner in which tbe ribs of the plesiosaurus articu- 

 late, throughout, by a single head, to the extremity of the transverse processes 

 of the vertebras only, — the structure of the humero-sternal parts, — and the cha- 

 racters derived from the head, approximate this animal most nearly to the la- 

 certae. By its teeth, on the other hand, it is allied to the crocodile : while its 

 small nostrils and multarticulate paddles are features in which it resembles 

 the ichthyosaurus. 



In Plate XXI. fig. 1, 2, 3, is represented the posterior portion of the lower 

 jaw of some saurian animal, perhaps the plesiosaurus, found in the lias at Wes- 

 •ton, near Bath, by Colonel Birch, With it was found the bone, figures 4, 5, 6; 

 probably an humerus, but very different in its contours from those of the ple- 

 siosaurus which we had previously met with. Perhaps it may be a new spe- 

 cies ; but as it probably belonged to the same individual with the jaw-bone 

 accompanying it, we cannot speak with certainty of either. 



Colonel Birch has lately procured two specimens, which exhibit the humero- 

 sternal parts of this animal in situ. They confirm the place we assigned to 

 these bones, as figured in our former memoir ; but we still wait for more illus- 

 trative specimens before we endeavour to figure the whole of this part. At 

 the point of the clavicular furcula there appeared to be a complex apparatus 

 of bones, probably a regular sternum ; but this part was too much fractured 

 to be much relied upon. The coracoid bones had a somewhat greater length, 

 from their anterior to their posterior tip, than those before figured ; but as 

 they belonged to an animal of much greater size, the proportion may perhaps 

 be modified in age. 



Attached to one of these specimens, was a series of vertebrae exhibiting the 

 cervical, dorsal, and lumbar vertebrae in situ : this was important, as confirm- 

 ing the position assigned to those figured in the former paper, which were 

 loose, and had been often deranged ; the arrangement assigned to them is 

 however in every instance confirmed by the series now mentioned. 



In Plate XXII. are figured an os ilium? fig. 3; an os pubis, fig. 2; and 

 a femur, fig. I ; all found with other bones of the plesiosaurus. From the 

 inspection of specimens in which the humerus and femur have been found 

 together, it appears that they are both much of the same size ; so that pro- 

 bably in this animal the difference between the length of the anterior and 

 posterior e.vtremities, observed in the ichthyosaurus, does not exist. 



