AND AVES OF NORTH AMERICA. 



GO-A 



From the above, four points may be derived: 1. That the ribs are continued to the sacrum in this type, a char- 

 actor not before pointed out among its representatives in this country or Europe, and one in which it differs from the 

 Crocodilia from the Cretaceous to the present period inclusive. 2. That the sacral diapophyses articulate with two 

 vertebrae Instead of one, a point similarly exceptional with the last point. 8d. That in both these points this type 

 approaches the Dioynodontia and Dinosauria, as it docs in some others, 4th. That the B. lepturus belongs to a dif- 

 ferent species from that from N. Carolina, last described, in having at least three diapophyses with double articulation 

 near the extremity instead of one, and to a different genus from the same, because several of these are cylindric in the 

 former, and broadly flattened in the latter. 



VV hioh genus is distinct from Belodon is difficult to ascertain. If wo suppose 15. oarolinensis to represent it, as it 



certainly docs in cranial oharacter* and other respects, the North Carolina specimen will represent another genus. 



since a, sacral vertebra of B. oarolinensis presents all the characters of that of B. lepturus. 



The centra of the vertebra are very muoh oompressed, and the articular faces flared out at the margins. The 

 faces are wide vertical ovals and distinctly concave. The posterior face of the supposed last dorsal is flattened, and 

 presents two slightly swollen triangular planes, each from the facet of the margin. 



The neural spines of the anterior vertebra) are shorter and wider, of the posterior more elevated and narrower. 

 The rib supporting the anterior zygapophysis is very prominent in all, as is that defining the margin of the neural 

 arch. They include a, short vertical concavity between them, giving the vertebra; a, marked character. 



The caudals are very much compressed, more so than in B. Ppriscus, though since they are median in the series, 

 and those of the latter are proximal, there would probably be a, greater resemblance between the homologous ones, 

 'fhe articular extremities are vertically oval, and but little flared at the margins. The neural arch with its apophyses 

 is oompressed. The diapophyses project just below the base of the arch, and arc depressed and stout. 



Measurement). M. 



Vertebra, 1st, type, 0.18 



Do. height neural spine from canal, 0.10 



Do. length diapophysis, 0.020 



Do. " centrum, 0.05 



Do. diameter centrum, middle, O.021 



Do. " " articular face, 0.055 



Do. " " vertical, articular face, O.050 



Total elevation type 2d, 0.1951 



Do. neural spine from canal, 0.1.22 



Do. width do., 0.04 



Do. length centrum, 0.05 



Do. diameter (transverse) cent, mm middle, 0.02J1 



Do. " " " artle. face, 0.054 



Do. " vertical " " O.OO 



Do. elevation type 8d, 0.186 



Do. neural spine from canal, 0.11 



Do. length centrum, 0.040 



Do. diam. (transverse) centrum at middle, O.032 



Do. " " " arfio. face, 0.0(11 



Do. " vertical " " 0.0G2 



Do. expanse anterior zygapophyses, 0.07 



Do. diameter neural canal, 0.02 



Length diapophysis, 0.082 



The neural canal in the vertebra, first described, is narrower and more elevated than in the last, dorsal. 

 A chevron bone has nearly cylindric limbs and short common junction of the same. Their proximal extremities 



are considerably expanded, but not, so as to meet on the median line. They are very oblique backwards and inwards. 



Distal extremity strongly striate. 



