586 



BRITISH FOSSIL REPTILES. 



which bifurcates to strengthen tlie humeral and coracoid surfaces, and to add to the 

 thickening of the articular end of the bone. Phillips notes the modification of 

 structure of tiie basal three inches of the blade, indicative of coarse or partial ossification 

 of an original cartilaginous superscapuha, the proportions of whicli element would thus be 

 more crocodilian than lacertian. The resemblance of the blade-bone of Cetiosaurus to 

 that of Scelldoi<futnis has already been noted. But the production of the anterior or 

 humeral angle of the articular end is somewhat greater, approaching that in TL/l(eosaiirus. 

 The length of the scapula of Cetiosaurus lovc/us is 4 feet 6 inches, the breadth of the 

 articular end is 2 feet 2 inches, the least breadth of the body of the bone 10 

 inches. 



The humerus of Cetiosaurus seems far from exhibiting the outstanding plates and 

 ridges for nuiscular attachments, such as we see in Omosaurus (PI. 70, figs. 1 and 2) and 

 the larger existing lizards {Ilydromurus, Monitor), which run swiftly on land ; they are 

 even more feebly indicated than in the Ci'ocodiles, but much of this inferiority may be 

 due to posthumous injury and abrasion in the present huge fossils. 



The head of the humerus, fig. 4, s, a, is an elongate, semi-oval, narrow convexity, 

 broadest at the middle, which projects toward the hinder or anconal surface of the bone, 

 as in Lizards and Crocodiles ; the degree of the projection is shown in the outline of the 

 proximal end of the bone, at c, fig. 4, a. 



The ridge from the radial side of the proximal third 

 of the shaft (fig. 5, Zi), answering to the ' pectoral ' or 

 ' deltoidal ' one in the Mammals, commences, as in the 

 Monitors, near the head, not, as in the Crocodiles, abru[)tly 

 at some distance below ; it has suffered abrasion in the Kirt- 

 lington specimen, yet seems not to have stood out in the 

 same relative degree as in Omosaurus, or as in the Monitor, in 

 which, as in the Crocodile, it is bent toward the fore or 

 palmar side of the bone. 



The shaft of the humerus in Cetiosaurus is subcom pressed, 

 subtrihedral, through an obtusely angular longitudinal low 

 ridge or prominence, on the anconal side (fig. 4), continued 

 from below the head to near the distal end, inclining toward 

 the radial side. There is no trace of the distal ridge from 

 that border of the shaft which, in Monitors, answers to the 

 'supinator' ridge in Mammals (PI. 70, fig. 6, e). The 

 more prominent of the two distal articular convexities, that, 

 viz., for the head of the radius, is feebly indicated ; the back 

 ))art of the convexity for the ulna is traceable at the worn 

 distal end of the bone (fig. 5, d). 



Ulna, Ce//(;sa«;iw /0Hy«s, -Jjtli nat. .„, , i i • i. • i I'lI i- 1 1 ■ 



size. (Phps., diagr. eiii, p. 275.) ^^^6 pcctoral and supuiator ridges are still more feebly in- 



Fir,. Ck 



