FOSSIL REPTILES OF DORSET. 25 



dorsal vertebrae, portions of several ribs and a phalangal bone. 

 The vertebras are characterized by the extreme shortness of the 

 centra, which are four and a-half times as broad and four times as 

 high as they are long, such as is not found in any other species of 

 Plesiosaurus. They are hollow in the middle and swollen near the 

 circumference ; in this they approach the Ichthyosaurian type, but 

 differ in the anchylosed neurapophyses, which bear long trans- 

 verse processes directed upwards and outwards, and in the neural 

 spines being long and straight ; the phalangal bones have the usual 

 Plesiosaurian elongated form and constricted in the middle ; the ribs 

 have simple flattened heads. From the Kimmeridge Clay, Kim- 

 meridge, presented by me to the British Museum. 



PLESIOSAURUS BRACHYSPONDYLUS, Owen. 



The remains of this species, consisting of vertebrae only, have 

 been found in the Kimmeridge Clay in the neighbourhood 

 of Weymouth. The articular surfaces of the vertebrae are very 

 slightly concave with a small round depression, but no convex 

 rising at the centre. The vertebrae of the fore part of 

 the neck are more compressed longitudinally than those of 

 the hind part towards the trunk, where they regain more of 

 the ordinary Plesiosaurian proportions. Sir K. Owen concludes 

 that Pies, brachyspondylus had a large and heavy head. 

 PLESIOSAURUS MANSELII, Hulke. 



This species is described by Mr. Hulke in the twenty-sixth 

 volume of the "Quarterly Journal of the Geological Society "on the 

 evidence of 86 vertebrae, the left humerus and femur, the distal 

 ends of the right humerus and femur, coracoid, ribs, and phalangal 

 bones. Although several of the vertebrae are, missing the united 

 length of the rest, including the anchylosed axis and atlas, 

 which are preserved, is eighteen feet; the ribs are flattened, 

 rough at their extremities, and correspond exactly with the 

 projecting processes of the dorsal vertebrae ; the length of the neck 

 cannot be ascertained with any certainty, as several vertebrae from 

 near the head and the trunk are missing, but the combined length of 

 those preserved is five feet. The length of the humerus is two feet 



