140 Prof. H. G. Seeley. The Shoulder Girdle 



Fig. 7. — Clavicular arch of Murcenosaurus platyclis, showing CI, the clavicles, rest- 

 ing upon Int., the interclavicle. 



the inner borders of the scapnlo-coracoid vacuities. They terminate 

 in transverse sutures, in advance of which the scapulas extend for 

 8 inches, forming large wide flat plates, with oblique slightly con- 

 cave anterior borders. These scapulas meet in the usual way by a 

 median suture for about 4 inches, anterior to which is a long median 

 vacuity or foramen, 3 J inches long and more than 1 inch wide, with 

 sub-parallel sides, which is bounded in front by a posterior concavity 

 in the interclavicle. A similar long median notch is seen between 

 the scapulae in the Leeds Collection (Brit. Mus.), No. 27, and in that 

 specimen there is a similar, though smaller, interclavicle, more imper- 

 fectly preserved. 



The anterior transverse bar of the interclavicle now described is 

 defined by the clavicles which rest upon the bone. It is 7 inches 

 wide. Owing to the contour of the clavicles, its lateral halves 

 increase in depth to about an inch as they extend outward. The con- 

 cave median notch in the anterior border is less than an inch wide. 

 It corresponds in form and size with the notch on the posterior border 

 of the bone, but is rather shallower. Between these opposite con- 

 cavities which indent the interclavicle the antero-posterior measure- 

 ment is 2J inches. This median part of the bone, which forms the 

 wide longitudinal bar between the clavicles, is 2J inches in transverse 

 measurement anteriorly, but widens posteriorly to 4 inches. Owing 

 to the way in which the lateral margins are concavely defined by 

 the overlapping clavicles, all the contours are somewhat unsym- 

 metrical from distortion. 



The right and left bones are unequal in length as preserved : one 



