92 



THE EXTINCT BATRACHIA, KEPTILIA 



Pig. 27. There was when the bone was complete, a 



double head, the anterior or superior apparently 

 for articulation with the coracoid ; the inferior, 

 to receive the proximal end of the humerus, 

 whose condyle is adapted to it both in size and 

 shape. It is a flat bone curved in the direction 

 of its plane, which is vertical, and narrowed 

 distally, where it is broken off. It is expanded 

 proximally into two heads of which the support 

 of the inferior is in the general plane, while that 

 of the superior is obliquely transverse to that 

 plane : this head, which I believe to be the 

 anterior and attached to the coracoid, is broken 

 off. The inferior articular face is slightly con- 

 cave ; it is rugulose for an articular cartilage, 

 and its plane is exactly transverse to the long 

 axis of the bone. Its form would be vertically 

 oval but for an expansion on what I suppose to 

 be the outer side. The inner side is characterized by an obtuse longitudinal ridge, which 

 extends upwards and backwards from the anterior head and soon disappears. A simi- 

 lar ridge is seen in the ischium of Crocodilia. As this ridge disappears from the inner 

 side, a- more obtuse one appears on the outer, and is in line with the subtransverse expan- 

 sion of the neck of the anterior head ; it soon reaches the posterior margin of the bone, 

 which it thickens. Between this point and the posterior head, the margin is thin and 

 acute. A more imperfect specimen of the same element from the same side (the right) of 

 a rather smaller individual exhibits similar characters. 



As compared with the scapula of Iguanodon, Hylaeosaurus and Scelidosaurus, a strong- 

 resemblance is seen in the marked distinction of the outline of the glenoid cavity, and the 

 existence of a large distal depression of a subtriangular form. The anterior expansion is 

 broken away, but from the indications at the fracture was probably well developed. 



The proportions of the larger scapula indicate a gigantic animal fully equal to the 

 known Hadrosauri ; the humeral support agrees with that bone in the latter. The 



dimensions are as follows : — 



In. 



Length of fragment on posterior margin, 1 3.9 



Depth proximally (greatest), 7.2 



" distally, 4 



