372 FOSSIL REPTILES. 



SO that its dimension, from front to rear, is nearly triple the 

 transverse measurement. Its anterior edge does not appear to 

 have had the emarginations, which are remarked in most of 

 the saurians, and it also wants the hole which is usually seen 

 in the disk. 



The omoplate, in the designs of Mr. Conybeare, is long, 

 narrow, elevated by a not very salient crest, and divided 

 transversely into two parts. In front, from one omoplate to 

 another, is a transverse crest, in the form of a crescent, whose 

 convexity, directed hindvvards, would unite to the anterior 

 extremities of the two coracoid bones. This Mr. Conybeare 

 calls the sternum, and gives it no longitudinal apophysis, so 

 that the two coracoids would unite through almost the totality 

 of their internal edge. In the skeleton of Lyme these parts are 

 concealed, by vertebrae and portions of the ribs, and probably 

 their osteology is not yet completely made out. 



This skeleton reveals the pelvis much better. It appears 

 that its ventral part, composed of the pubes and ischia, some- 

 what resembled that of the land-tortoises, that is to say, the 

 ossa pubis joined each other, and the ossa ischia joined each 

 other by a symphysis, and the posterior extremity of the first 

 joined the anterior extremity of the second, so as to make, on 

 the total, a suture in the form of a cross, and to leave on each 

 side a round hole analogous to the oval foramen in man, and 

 the majority of the mammifera. 



In the greater number of reptiles this union of one pair of 

 bones with another does not take place, and the two ovalary 

 foramina unite in the skeleton in one large common aperture. 



The pubis appears to have been larger, and especially more 

 broad towards the cotyloid cavity, than the ischion. This last 

 is wide and fan-shaped. 



The ilia, of which only one remains, and is displaced, were 

 narrow, and not voluminous. 



The extremities of the plesiosaurus are more elongated than 

 those of the ichthyosaurus, and the hands and feet constitute 



