PICEOCLEIDtrS. 147 



vertebrae, which are deeper in proportion to their length and width, though otherwise 

 very similar; so far as is known, the shoulder-girdle and humerus are not distin- 

 guishable from those of P. beloclts. Further material will probably justify the 

 separation of this form as a distinct species, but for the present it need not be named : 

 the specimen (R. 2429) here referred to, including the nearly complete shoulder-girdle 

 and left humerus, with some posterior cervical and the pectoral vertebr^E, an anterior 

 dorsal, and some ribs, may be taken as the type. 



E. 2439 (Leeds Coll. 41). Portion o£ a skeleton of an adult individual. The parts preserved 

 include the six posterior cervical vertebrae, two pectorals and the first dorsal, some 

 dorsal ribs ; the shoulder-girdle, wanting the interclavicle and the posterior part of the 

 coracoids ; the left humerus. The shoulder-girdle, so far as preserved, is closely 

 similar to that of the type specimen of Picrocleidus heloclis^ and the same mny be said 

 of the humerus. The vertebrse, on the other hand, have centra in which the height is 

 greater in proportion to the length and width than in the type species. 

 The dimensions (in centimetres) of this specimen are : — 



Vertebra; 



Length of centrum in mid- 



Posterior 

 cervical. 



Last 

 cervical. 



First 

 pectoral. 



Second 

 pectoral. 



Anterior 

 dorsal. 



ventral line 



3-9 



3-7 



3-8 



3-8 



4-0 



Width of posterior face of 













centrum 



5-5 



6-0 



5-9 



6-7 



5-3 



Height of posterior face of 













centrum 



4-3 



4-4 



4-4 



4-4 



4-6 



Height to top of neural spine. 



14-8 



? 



15-6 



15-3 



lo-4 



Shoulder-girdle : 



Scapula : greatest length 22'7 



Coracoids : width of the combined bones between the 



postero-external angles of the glenoid cavity . 29'5 



width of united bones at narrowest 19'7 



antero-posterior diameter of the eoraco-seapular 



foramen 7'9 



transverse diameter of the coraco-scapular foramen 7"9 



Humerus : length 22-5 



diameter of head 5*9 



greatest width at proximal end 8'0 



diameter of shaft at narrowest b'o 



width of distal expansion 12'6 



E. 2739 (Leeds ColL 33). Portions of the skeleton, including basioccipital with part of basisphenoid 

 and parasphenoid, twenty-six cervical vertebrae mostly with the arches and ribs, 

 two sacrals with the sacral ribs, one anterior caudal, some ventral ribs, both radii, 

 odd paddle-bones, portions of ilia, ischia, and pubes. 



In this specimen the fusion of the ribs and neural arches with the centra of the 

 cervical vertebrae is complete, and the same is the case in the single caudal preserved. 

 In the sacrals the ribs remain distinct (text-fig. 71) and it is interesting to note that 



U2 



