628 



PROF. H. Gr. SEELEY ON THE REPTILE 



tion. Hence the surface is narrower, more vertical, and more 

 elongated, and especially more . concave than in the Crocodile ; but 

 there is a slight angle rising as a short ridge from the hinder exte- 

 rior corner of the articulation, directed upward and forward, repre- 

 sented in Crocodiles by a similar fainter ridge. Only the posterior 

 part of the coracoid suture is preserved. It makes an angle of 45° 

 with the humeral surface when seen from the front, and an angle of 

 90° when seen from the side. The bone is narrower in front and 

 behind than in the middle, where it is 12 millim. thick. So much as 

 is preserved is 2 j centim. long. Its external margin is convex ; the 

 internal margin appears to have been straighter. At the angle above 

 its union with the humeral surface there is a small depression. 

 Owing to the fact that the bone thickens externally with the humeral 

 surface, the area anterior to that surface is concave and smooth. 

 The concavity is directed obliquely downward and forward. There 

 are indications that the anterior margin of the bone was deve- 

 loped into an angular ridge, which may have corresponded with 

 that of the Crocodile. The visceral surface of the bone was concave 

 from above downward, and, though crushed, appears to have been 

 flatter from side to side, more rounded on the anterior margin, and 

 more compressed on the posterior margin about the humeral articu- 

 lation than in Crocodiles. The blade of the bone, however, was 

 similarly constricted at the fracture, , where it is less than 2 centim. 

 wide and about 1 centim. thick as- preserved, convex in front and 

 flattened behind. Though this bone is on the whole Crocodilian in 

 its characters, it is also Dinosaurian, and perhaps makes the nearest 

 approximation to the scapula figured by Prof. Marsh in the fore 

 limb of his five-toed Dinosaurian Camptonotus dispar. 



Struthtosaurtjs attstriactts, Biinzel. 

 (See Biinzel, pi. v. figs. 1-6, p. 11.) 



The hinder part of the skull of a Dinosaur figured by Biinzel is some- 

 what difficult to describe, on account of the obliteration or obscurity of 

 the sutures ; and yet the anterior surface of the roof of the brain-case 

 is margined by a well-marked transverse suture limiting the front of 

 the parietal bone — a suture similar to that which persists in the skull 

 of the Fowl long after other sutures have become obliterated in the 

 hinder part of the cranium. The specimen certainly presents a remark- 

 able resemblance to the back of the skull of a bird ; but I believe that 

 Biinzel has attached more than due importance to this similitude, 

 owing to the circumstance that the true nature of the Dinosaurian 

 skull was even less perfectly known when he wrote than it is now. 

 He has supposed his specimen to be more complete than, in truth, 

 it is, being unaware, or unmindful, of the evidence that, external 

 to the parietal bone, the Dinosaurian skull has - an upper arch or 

 bar, like that so common in reptiles and unknown in birds, and 

 that, as a rule, there is also a lower malar arch, more or less deve- 

 loped, behind the orbit ; and therefore it happens that the bone which 

 he regarded as tympanic or quadrate, and interpreted as Crocodilian, 

 is the paroccipital or opisthotic of modern anatomists, as, indeed, 



