hatcher: diplodocus (marsh) 



41 



Measurements of the Sternals. 



Greatest length 21 J in. 553 mm. 



" breadth 13f " 340 " 



•" thickness 3^- " 89 " 



The Clavicles. 

 Thus far no clavicles have been found in the Dinosauria. Since the Lacertiha 

 are known to possess clavicles it is not unreasonable to suppose that tliese bones were 

 present in at least some genera of the Dinosauria. Associated with the skeleton of 

 No. 84 there was found a peculiar bone which from its general form and size might 

 very well have functioned as a clavicle. This 



bone is 485 mm. (IQi in.) in length. Through- ^ 



out the greater portion of its length it is almost 

 circular in cross section and about 45 mm. in 

 diameter. It is bifid at one extremity and 

 slightly expanded and somewhat flattened at the 

 other. It is strongly curved, especially toward 

 the bifid extremity. It is asymmetrical. If this 

 bone is not a clavicle it is difficult to assign it 

 any other position in this skeleton. It evidently 

 is not a rib, and from its size and shape it could 

 very well have been a clavicle ; moreover its po- 

 sition in the quarry, between the sternals and 

 coracoids, would seem to afford additional exi- 

 dence for assigning it such a position in the 

 skeleton. Two views of it are shown in Fig. 13, 

 a, h. If a clavicle, the convex surface was evi- 

 dently the external, while the strongly inflected, ^^f^- ^^- Supposed clavicle of Bip- 



1.^, , ., TT ,1 , ,, lodocus carnegii (No. 84) ; a, front view ; 



bifid extremity would seem to have been the , . . ,. 



*^ o, external view. A little less than one 



inferior and the broad, spatulate extremity the gixth natural size. 

 superior. We must, however, await future dis- 

 coveries to determine definitely the nature and position of this bone ; though I am 

 at present strongly inclined to the opinion that it was a clavicle. 



The Ribs. 

 The cervical and sacral ribs and the fixed ribs of the eleventh dorsal have been 

 described in connection with their respective vertebrae and need no further notice 



