182 



or possibly Juraspic beds at the base of this granitic mountain, and its occur- 

 rence where found was doubtless accidental. 



PELECORAPIS, Cope, gen. vov. 



This genus embraces tishes with strongly ctenoid scales and abdominal 

 ventral fins. There is a spinous dorsal fin, apparently short, and not continued 

 over the ventrals. The ribs and apophyses are slender, and {\\c dorsal ver- 

 tebrae short and pitted. The ])uljic bones consist of two antero-posterior 

 plates, in contact on the middle line. The anterior portion i)r()jects to a 

 median angle, and there is an angular projection of the lateral border. From 

 the angle formed by these borders, a long, cylindric rod projects forward 

 beyond the plate ; those of opposite sides slightly converging. 



The general relations of this form are to the tiimilies which combine the 

 features of the orders of physoclystous and physostomous fishes, viz, Scom- 

 hresocidcE, Afheriniclce, etc. The pelvis has considerable resemblance to that 

 of those families, I)ut especially to that of Exocosius. From this it presents 

 subordinate ditferences. 



PeLECOKAPIS VAKIUS, S]>. 7100. 



Represented by portions of perhaps two individuals, the larger of wiiich 

 includes a considerable peart of the body, the head and tail l)eing absent. 

 On this specimen, it is evident that the scales diminish in size toward the 

 posterior part of the body, where they are small ; on the anterior region, there 

 are two scales exposed, in an oblique series, in si.x millimeters; on the pos- 

 terior region, three and one-half and four in the same. The concealed 

 portions of the scale are sculptured with minute contiguous concentric grooves, 

 without any radii. The exposed portion is thickened with a cementum-like 

 layer, which is marked witii a few radiating lines of p(jres, which sometimes 

 unite into irregular grooves. Teeth of the comb numerous and strong. 

 Depth of l)ody at pelvis, 0"'.074 ; length of pelvis, 0"'.040 ; of lamina, (r.022 ; 

 of rod, 0"'.022 ; greatest width of pelvis, ()"\()23 ; width at basis of rods, 

 O^.OH; length of seventeen consecutive vertebrae, 0"'.105; diameter of a 

 dorsal vertebra, 0'".007. 



Discovered by Professor Mudge in a lead-colored <'lny, [)rol)ably of the 

 Benton epoc-ii, twenty feet l)elow the Iitnceramvs bed, two miles west of 

 Sililev, Kansas. 



