32 Colorado College Studies. 



Pelecorapis varius Cope. 



Plate II, tigs. 1 and 2. 



Pelecorapis varius Cope. Report (Hayden) U. S. Geological Sur- 

 vey of the Territories, Vol. II, p. 182. 1875. 



Body rather eloiif,'ate, tapered-elliptic, compressed, deep- 

 est in the front- middle region near and in front of the dorsal 

 fin and taperimj; thence slowly backward to candal pednncle; 

 head abont 4^ in total leii<i;th; muzzle not elongate; mouth- 

 cleft reaching to about opposite posterior border of orbit; 

 premaxillary extending backward a little more than half of 

 the distance from tip of snout to below anterior border of 

 orbit, apparently articulated so as to be movable with refer- 

 ence to maxillary: premaxillaries and anterior portion of 

 dentaries armed with moderately large, recurved, intervalled 

 teeth, maxillaries with small and narrowly interspaced teeth; 

 clavicle stout: pelvis of two broad, irregular, lamelliform 

 bones, either of which presents toward the median plane, 

 along which their edges are in contact, a large thin, longi- 

 tudinally oblong, inferiorly concave wing, or scoop-shaped 

 portion, thickened posteriorly, the portion exterior to which 

 is subquadrangular, thicker, and in part transversely convex 

 on its under surface. The scoop-like portion extends con- 

 siderably further backward than the quadrangular, and from 

 the angle formed by the outer border of the former and the 

 posterior border of the latter a strong, anteroposteriorly 

 trending articular process springs rather abruptly down- 

 ward. A portion of the bone, chiefly of the thicker quad- 

 rangular portion, is produced far forward as a sharp splinter- 

 like process, or spine, the inferior surface of which is trav- 

 ersed near its inner margin by a shallow groove. The spine 

 is directed as a radius from the articular process, and a little 

 obliquely, so that the two spines of the pelvic bones slightly 

 converge. Dorsal fin consisting of about 20 rays, the first 

 one of which is apparently simple or spinons, the others dis- 

 sected, the 8 or 10 anterior dissected rays being moderately 

 tall and strong and placed in rather close succession, while 

 the posterior are small and well intervalled, the change from 

 larger to smaller rays being apparently quite gradual. The 



