THE CYPRINODONTS. 151 



teeth with a shoulder, as in Anableps and Rivuhis. Eye one and one- 

 half times in the snout, twice in the interoi'bital space, and four and three 

 fourths times in the head. Scales large ; on head and body to tips of pec- 

 torals thick, convex, smooth, and glossy ; on hinder portion of body flat, 

 thinner, with fine strise, not glossy ; breast naked, more of the lower surface 

 covered on this species than on 0. Cuiieri or 0. Pcntlandii ; about four series 

 of scales on the cheek ; more or less of the top of the snout naked ; verte- 

 bral series irregular. Dorsal fin originating about half way from occiput to 

 base of caudal, its third ray above the first anal ray, which is midway be- 

 tween base of pectoral and caudal. Base of anal extending a couple of rays 

 farther backward than that of dorsal. Caudal broad, as long as head, 

 rounded on the posterior margin. Pectorals reaching little more than half 

 the distance to anal. Intestine convolute, one and a half times to twice the 

 total length. On old individuals the nape and back of the head become 

 strongly arched, the latter becoming quite prominent, and the scales are lost 

 from the interorbital space and forward. The thickness and the worn ap- 

 pearance of the scales suggests a great deal of rubbing against the rocks 

 or gravel. On specimens of three inches the convex and glossy scales are 

 hardly to be detected ; and those of two inches are much like the Funduli, 

 the head and shoulders being less prominent and the body more compressed. 

 As in the other species the main osseous support of the caudal is a single 

 very broad fan-like ray, in which there is little or no evidence of fusion, 

 passing directly backward from the vertebrae. 



Eight inch specimens are olivaceous on the back, lighter to whitish on 

 the lower half of the body. The scales being lighter colored in their cen- 

 tres give the back a tessellated or reticulated appearance. The fins are 

 brownish, more or less clouded. Young less than half grown are much 

 lighter colored ; they have a narrow streak of darker along the middle of 

 the flank, faint transverse bands or series of spots or blotches on back and 

 fins, and a yellowish tint below the gills. In this stage snout and eye have 

 about the same length. When about two inches in length the color is much 

 lighter, there are transverse streaks of brown on the fins, clouded blotches, 

 formed of puncticulations, on the flanks and in a somewhat irregular series 

 along the middle, and the cheeks and a streak below the dark hne on the 

 middle of the side are silvery. The amount of silvery space on the lower 

 half of the body varies greatly. 



Abundant in Lake Titicaca. 



