PLECTOSPONDYL1 CYPRINIDAE LEPIDOMEDA JAEROVII. 643 



the second dorsal spine is wider than the first, and so deeply grooved behind 

 as to represent a V in section ; it also extends to the extremity of the first, 

 while it is shorter in P. argentissimiis. The remaining dorsal spines are less 

 distinctly enlarged and ossified ; those of the ventrals are less developed, 

 and their apices, instead of being free, continue into the terminal articulated 

 portion. The pectoral radii are scarcely enlarged at all. The base of D. I. 

 is nearer the basis of the caudal fin than the end of the muzzle by the 

 length of the latter to the posterior nares. Caudal fin deeply forked. Total 

 length, CT.OS5; length to the basis of the caudal fin, O m .OGS5; to the basis 

 of the anal, O m .047; to the basis of the ventral, O m .0325; length of the head, 

 CT.018; length to the orbit, O m .043; width at the posterior nares, CT.OOG; at 

 the middle of the pterotic, O m .009. Color silver to half way between lateral 

 and dorsal lines ; the upper part of it underlaid by a lead-colored band ; 

 a median dorsal black band from front to caudal fin. 



The plate affords a view of this species in profile and of the ventral 

 aspect. 



Numerous specimens from the Colorado Chiquito River, Arizona, col- 

 lected by H. W. Henshaw, No. 5, X. P. The largest species of the group. 



LEPIDOMEDA JARROVII, Cope. 

 PLATE XXVI, FIGS. 1, la. 



Lcpidomcda jarrovii, COPE, Proc. Am. Phil. Soc. Phila., 1874, 133. Id., Rep. Plagop. 

 & Ichthy. Utah, 1874, 6. 



A species resembling the last in many respects, but differs in a greater 

 elongation of form, weakness of squamation, and peculiarity of coloration. 

 The fin radii are similar in number and character, but the dorsal is fur- 

 nished with more slender spines. The chin projects a little beyond the 

 upper lip when the mouth is closed. The depth of the body at the ventral 

 fins enters the length of the basis of the caudal 5 to 5.25 times, and the 

 head enters the same four times. The eye is larger than in L. vittata, enter- 

 ing the length of the head 3.25 times and equaling the interorbital width. 

 The end of the maxillary bone reaches the line of the anterior border of 

 the orbit. The pectoral fin reaches the ventral, but the latter does not 

 attain the vent. The scales are difficult to detect; there are 51 transverse 

 series between the head and the dorsal fin. Total length, O m .OSl ; length 



