Page:Synopsis of the Exinct Batrachia and Reptilia of North America. Part 1..pdf/65

 AND AYES OF NORTH AMERICA. 60-A From the above, four points may be derived: 1. That the ribs are continued to the sacrum in this type, a char-acter not before pointed ont among its representatives in this country or Europe, and one in which it diffem from the Crocodilia from the Cretaceous to the present period inclusive. 2. That the sacral (1; .apophyses articulate with two vertebra instead of one, a point similarly exceptional with the last point. 3d. That in both these points this type approaches the Dicynodontia and Dinosanria, as it does 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. Which genus is distinct from &lotion is difficult to ascertain. If we suppose B. earolinensis to represent it, as it certainly does in cranial characters and other respects, the North Carolina specimen will represent another genus. since a sacral vertebra of B. carolinensis presents an the characters of that of B. lepturus. The centra of the vertebra are very ranch compressed, 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 vertebrae 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 vertebrae a marked character. The cauclals are very much compressed, more so than in 13. priseus, 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. The articular extremities are vertically oval, and but little flared at the margins. The neural arch with its apophyses is compressed. The diapophyses project just below the base of the arch, and are depressed and stout. Measurements. Jr. Vertebra 1st type, 0.18 Do. height neural spine from canal, 0.10 Do. length diapophysis 0.026 Do. °entrain, 0.05 Do. diameter ceutrum 0.021 Do. articular face, 0.055 Do. vertical, articular face, 0.059 Total elevation type 2d, 0.1951 Do. neural spine from canal, 0.122 0.04 Do. width do., Do. length centrism, 0.05 Do. diameter (transverse) centrum middle, as Do. artic. face, ri Do. vertical 0.023 0.034 0.06 Do. elevation type 3d, 0.186 Do. neural spine from canal, 0.11 Do. length centrum, 0.049 Do. diam. (trausvcrse) centrum at middle, (1.032 Do. artic. face, fi Si Do. vertical 0.001 0.062 Do. expanse anterior zygapophyscs, 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.