Page:Synopsis of the Exinct Batrachia and Reptilia of North America. Part 1..pdf/98

 92 TILE EXTINCT BATRACIII-1, REPTILIA Fig. 27. There was when the bone was complete, a double head, the anterior or superior apparently for articulation with the corticoid; the inferior, to receive the proximal end of' the lunnerus, whose condyle is adapted to it both in. size and shape. It is a fiat bone curved in the direction of its plane, which is vertical, and narrowed /h. distally, where it is broken off It is expanded proximal].) into two heads of which the support of the inferior is in the general plane, while that of the superior is obliquely transverse to that plane : this head, which I believe to be the anterior and attached to the cm acoid, is broken off The inferior articular face is slightly con-cave ; it is rugulose for an articular cartilage, and its plane is exactly transverse to the long axis of the bone. Its form would be vertically oral but for an expansion on what I suppose to be the outer side. The inner side is characterized by an obtuse longitudinal lidge, which extends upwards and backwards from the anterior head and soon disappears. A simi-lar ridge is seen in the ischium of Crocodilia. As this ridge disappears from the inner side, a more obtuse one appears on the outer, and is in line with the subtransverse expan-sion of the neck of the anterior head ; it soon reaches the posterior margin of the bone, which it thickens. Between this point and the posterior head, the margin is thin and acute. A more imperfect specimen of the same element from the same side (the right) of a rather smaller individual exhibits similar characters. As compared with the scapula of Iguanodon, Hylaeosaurus and Sceiidosaurus, a strong resemblance is seen in the marked distinction of the outline of the glenoid cavity, and the existence of a large distal depression of a subtriangular form. The anterior expansion is broken away, but from the indications at the fracture was probably well developed. The proportions of the larger scapula indicate a gigantic animal fblly equal to the known Hadrosauri ; the humeral support agrees with that bone in the latter. The dimensions are as follows:— hi. Length of fragment ou posterior margin, 13.9 Depth proximally (greatest), 7.2 '° distally, 4 QS