154 General Notes. [ February, 
as a Rhinocerus unicornis, with teeth approaching those of Hadro- 
saurus in characters. The accompanying figure 2 represents the 
element in question, one-tenth the natural size. Here the lateral 
elements are united on the middle line, which projects as an 
obtuse keel. The lateral processes are nearly transverse, and 
are impressed at their extremities by articular surfaces. The 
opposite extremity presents a facet on each side for a squamosal 
articulation with a flat bone (c, Fig. 2), in which the inferior 
bounding ridge projects much further than the superior one. 
This articulation cannot be for any other bone than the coracoid, 
and it resembles considerably the corresponding groove on the 
sternum of the crocodile. The general surface of the bone is 
dense, and does not resemble the imperfect ossification described 
by Hulke in the bone of similar character referred by him to 
Fig. 1. Fig. 2 
Fic. 1, Sternum of Diclonius mirabilis Leidy ; Fic. 2, do. of Monoclonius crassus 
Cope; both one-tenth natural size; c, coracoid facet. From the Laramie beds of 
Dakota and Montana, . 
Iguanodon? That the element in Monoclonius, represented in 
Fig. 2, is the sternum, seems very probable, and, if so, the ele- 
ments in Diclonius (Fig. 1) are sternum also, 
The T-shaped bone figured by Hulke, if inverted, would resem- 
ble the elements here referred to the sternum in Diclonius and 
-Monoclonius. Mr. Hulke describes a probable articular facet 
along its sides “ posterior ” (anterior) to the divergent bars, as - 
suggesting an articulation with an epicoracoid. This may cor- 
respond with the facet c in Diclonius and Monoclonius, which, I 
suppose, received the edge of the coracoid. This justifies the 
proposition of Baur,’ that this bone should be inverted, and that 
the supposed clavicles of Hulke and Marsh are posterior pro- 
1 Quarterly Journal Geological Society, 1885, pl. xrv. 
2 Zoologischer Anzeiger, No. 205, 1885, p. 2. : 
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