OPHTHALMOSAUKUS ICENICUS. 73 



long, approximately. The quadrate is massive and very extensively ossified ; its extreme 

 length is 13'5 cm., the width of the neck 6'8 cm. 



The scapula is very fully ossified, and the deflected antero-inferior angle forms a 

 definite and prominent process (Pacroraium). The length is 23 cm., the width of the 

 proximal expansion 14"8 cm. 



R. 2173 (Leeds Coll. 56). A caudal vertebra, a left humerus with radius, ulna, and seventeen other 

 paddle-bones. The humerus has the prominences on the anterior angles of its distal 

 end strongly developed on both its upper and lower surfaces ; the pisiform facet is very 

 small ; its length is 18'5 cm., the width of its distal end 15'4 cm. 



E. 2174. Atlas and axis with twenty-seven other prccaudal vertebrae and a femur of a young 

 individual. The original line of separation between the fused atlas and axis centra is 

 clearly marked, even on the floor of the neural canal, where in most cases it is early 

 obliterated. 



The dimensions of the combined atlas and axis centra are : height 5'3 cm., width 

 6"0 cm., length at neural canal 2'7 cm. The femur is only 4"7 cm. long, its distal end 

 being 3"2 cm. wide. 



R. 2163. Bones of the back of the skull of a small individual, including the basioccipital, basi- 

 spheuoid, stapes, one opisthotic, and quadrates. 



R. 2135 (Leeds Coll. 71), A series of vertebrse, including the atlas, axis, and thirty other precaudal 

 centra, together with twenty-four caudals from various parts of the tail. Also portions 

 of the coracoids, the right humerus, both radii, an intermedium, a pisiform, and fifteen 

 other paddle-bones. Some of these last are very thin and seem to have belonged to the 

 edge of the paddle ; their surfaces also are broken up by grooves into a number of 

 irregular areas with smooth surfaces, which may indicate that they were merely covered 

 with some sort of horny epidermal strticture. The atlas and axis, with the four 

 succeedincr vertebrae, are shown in text-fio'. 25, 



Some dimensions (in centimetres) of these specimens are : — 



Atlas and axis : length of centra 4-S 



width of centra S-1 



depth of centra 8-6 



Third cervical : length 2'8 



width 6-6 



depth 7'4 



Fourth cervical : length 2-8 



width 6-3 



depth . 6-9 



Total length of the six anterior vertebr£e (text-fig. 25) . . . 17'0 



Humerus : leugth 19-7 



R. 2188. Portion of basioccipital. About eighty-six vertebral centra, mostly crushed and broken, 

 with the exception of the posterior caudals, about fifty-four in number. Also a femur 

 and sixteen paddle-bones. The chief peculiarity about this skeleton is, that the basi- 

 occipital seems to have been formed by two centra, an anterior and a posterior, the 



L 



