302 Prof. H. G. Seeley — On Vogfs View of the Arcliceopteryx. 



show no trace of uncinate processes. There are free sternal ribs, 

 which the author supposes to have been fixed to an abdominal linear 

 sternum. The pelvis, well shown in the British Museum specimen, 

 is here said to be imbedded. Apparently its characters are alto- 

 gether different from those displayed in the first slab, since the 

 femora are in natural position ; and the fore part of the sacrum, 

 and apparently its hind part also, are laid bare without exposing 

 any trace of the long ilium or of the other pelvic bones. The tail 

 is very long. 



The pectoral and pelvic arches next come under consideration. 

 The author confesses to some doubt concerning the structure of the 

 shoulder girdle, which is quite free from the body. Two long 

 slender bones are directed backward ; these are identified as scapula3, 

 and it is observed that they are formed nearly as in Pterodactyles 

 and Birds. Between the slightly expanded anterior ends of the 

 scapulge is a bony mass which Professor Vogt regards as the 

 coracoids. I should rather suspect that this median mass is the 

 sternum, though in that case the coracoids remain unrecognized. 

 This view Vogt has considered and rejected. There appears to me 

 to be a groove on the anterior margin of this median mass, such 

 as would contain the distal ends of the coracoids, and from the 

 angle at which the coracoids probably met the scapula, they would 

 naturally lie beneath those bones, and, if the mud were soft 

 enough to receive them, would inevitably be squeezed into it. 

 Unless we thus identifj'' the sternum, there is confessedly here 

 a fundamental difference of structure from the bird ; but since the 

 expanded feathers enforce the presumption that the fore-limb was 

 used for flight, the conviction follows that flight was brought about 

 by development of the pectoral muscles attached to a sternum in the 

 usual way. This is the a priori view, and I see no evidence that the 

 so-called coracoids have an osseous union with the scapulae, or any 

 reason for supposing that the coracoids would here be placed in 

 a relation which has no parallel in birds, pterodactyles or bats. 

 I cannot accept Vogt's interpretation, merely because such a relation 

 of the coracoids as he suggests exists in some extinct orders of 

 reptilia which did not fly. The probability is strong against finding 

 an entirely new function for the coracoids in a flying animal. The 

 interpretation reminds one in kind of the already considered inter- 

 pretation of the skull : it may be excellent, but it requix-es excellent 

 reasons in support before it can be received. There is a further 

 point in which the shoulder girdle is supposed to be unlike that of 

 most birds. Prof. Owen described in the original slab what he re- 

 garded as the furcula. This bone is absent, or at least not visible, in 

 the second slab. It is sufficiently different from what might have 

 been expected, to have often suggested some doubt as to its true 

 nature ; but we were scarcely prepared for Vogt's suggestion that it 

 is the pubis. After quoting Prof. Owen's description of the pelvis of 

 Arcliceopteryx, the author expresses a belief that Prof. Owen would 

 not now formulate an opinion so positive as to its giving no evidence 

 of reptilian structure, since we know the pelvis of Dinosaurs better, 



