Page:Synopsis of the Exinct Batrachia and Reptilia of North America. Part 1..pdf/41

Rh on the hinder aspect of a dorsal has a disciform articular surface directed outwards and downwards : the prominence of its upper face is continuous with the lateral ridge of the neural spine. The anterior uplooking surface is equally small and little divergent.

Inches.

It may be observed the anterior caudals have a nearly round articular extremity one of them is a little wider than high, but they are too much distorted to furnish reliable measurements.

The portion of ilium preserved is an extremity. It is flat on one side and convex on the other. The shaft is solid. The articular extremity is oblique, and presents a truncate extremity, which is at right angles to a short recurved margin, which has been an insertion or articulation ; the flat surface is rugose distally. Long diameter of extremity, 2 in. .73 ; of shaft, 1.9 in. The articular faces of the extremity of the femur are at an open angle with each other, and are strongly concave in transverse section. The femur is here very fiat, with narrow margins : it becomes stouter with diminishing width. Distally the surface is marked by grooves and small foramina. What may be tibia is the basal frustrum of a wedge ; the articular faces broad, the outer margin narrowed ; the faces slightly concave. The inner margin is shorter than the outer, and the distal part of it presents a broad articular face. Some of the tarsal bones have been already described. There are thirteen metatarsals and phalanges. They are of stout proportions and are considerably constricted medially. Those of one series are square in section ; those of another, transverse ; those of the third transverse with one edge thinned or acuminate in section. Some of each form are more elongate than others.

Inches.

AMERI. PHILOSO. SOC.——VOL. XIV. 10