l62 



THE PERMO-CARBONIFEROUS RED BEDS OF 



The pubis (fig. 35) assigned to Cricotus has the inner side of the blade 

 sUghtly concave. The anterior end of the inner or lower edge is thin anteri- 

 orly, but the posterior half is much thickened and there is a flat articular face 

 for union with the bone of the opposite side. When the two bones were in 

 position there was a large and rather deep notch at the anterior end of the 

 pelvis. At the posterior end of the thickened portion there is a small, flat area 

 running up to the foramen and looking obliquely backward and inward, 

 probably for attachment with the ischium. The pubic foramen is near the 

 posterior end and, as in the reptilian genus Vara- 

 nosaurus, is incomplete behind. On the inner side 

 of the upper edge, just above the anterior end of 

 the foramen, or a little more forward, is a small, 

 knob-like tuberosity. 



The ischium. — There are several ischia in the col- 

 lection of the general form common in the smaller 

 Pelycosaurs. As this type is very abundant in the 

 collection it may be that it belongs to Cricotus. 



X %. No. 

 right side, 

 inner face; 



Humerus (plate 22, figs. 4 and 5, and fig. 36, ^'^-j^^T^tubis 'oi 

 a and b). — There are four humeri of a new type, a, outer face; 6, 



c inner gqsg. 



which are referred to the genus Cricotus. Three of 



these (No. 3419) are in excellent condition. They are pecuHar in their ex- 

 treme thinness and breadth. The articular surfaces of the ends are more 

 nearly parallel than is common in this bone in the Permo-Carboniferous 

 fauna. The proximal articular surface winds around the end of the bone and 



Fig. 36. — Cricotus sp. X 



(a) Articular face of proximal end, {b) articular face of distal end of humerus, No. 



3419. (Same bone as shown in plate 22, figs. 4 and 5.) 

 (c) Lower face, {d) upper face, (e) articular face of proximal end, (/) articular face 



of distal end of humerus of an immature individual. No. 3420. 

 (g) Distal end, (h) proximal end of femur, No. 3366. (Outline of articular faces of 



bone shown in plate 22, fig. 6.) 



descends upon the deltoid process. There is little or no widening of the end 

 to form a head, and the deltoid process is but an extension of the outer edge 

 of the bone, standing out at a low angle with the anterior face. The shaft is 

 very thin and wide. From the center of the articular face on the deltoid 

 process a sharp ridge passes downward and becomes the very thin outer edge 

 of the bone ; this knife-edge continues to the distal end of the bone, where it 

 terminates in a small facet, evidently for cartilaginous attachment. The 



