1905. ] ON THE SUPPOSED CLAVICLE OF DIPLODOCUS. 289 
9. Remarks on the supposed Clavicle of the Sauropodous 
Dinosaur Diplodocus. By Francis, Baron Nopcsa, 
EheD 
[Received June 6, 1905. ] 
(Text-figures 46-49.) 
It is still uncertain whether the extinct Dinosauria possessed 
clavicles. 
Considering the close relationship existing between these 
reptiles, the Rhynchocephalians, Parasuchians, and Birds—this 
last relationship being shown by the continuous tendency of 
Dinosaurs to specialize on most different occasions in bird-like 
manner—one is at first naturally imduced to believe that in 
Dinosaurs clavicles were present; but, as a matter of fact, bone 
after bone supposed to represent this element has had to be 
removed from this position. 
Hitherto only the family Ornithopodide is known to possess, 
in addition to scapula and coracoid, a curious further element in 
the shoulder-girdle, which was called clavicula, but may quite as 
well form only a part of the sternum (this double element being 
in one case united in the middle by bony matter). No other 
Saurischian or Orthopodous Dinosaur shows a clavicular ossi- 
fication. It is true that in the Sauropoda, besides scapula and 
coracoid, one or two flat bones are always present in the scapular 
region of the body: these, however, do not represent clavicule, 
but may with certainty be determined as ossifications of the 
sternum. ‘The discovery, therefore, of what may be called a 
supernumerary bone besides the sternal plates in two of the several 
Diplodocus skeletons known to science proves to be of quite 
exceptional interest. 
Hatcher, in his important Monographs of the Diplodocus 
skeletons Nos. 84 and 662 of the Carnegie Museum, describes 
this element as follows :—“ Throughout the greater portion of its 
length it is circular in cross-section, it is bifid at one extremity 
and slightly expanded at the other. It is strongly curved, 
especially toward the bifid extremity. It is asymmetrical.” In 
a more complete specimen (No. 662) than the former (84) it is 
‘“‘somewhat expanded and spatulate; the flattened extremity 
presents a slightly rugose surface, as though it had been imbedded 
in cartilaginous or muscular tissue, and this together with the 
bifid nature of the other extremity has suggested the possibility 
that the bone might be an os penis.” After the description of 
this bone, however, its asymmetry is regarded by this eminent 
paleontologist as a weighty argument against its being an os 
penis, and therefore its identification with the clavicula is 
advocated. 
* Communicated by Dr. A. Smita Woopwarp, F.R.S., F.Z.8. 
Proc. Zoou. Soc.—1905, Vou. II. No. XIX. ig) 
