146 Field Columbian Museum — Zoology, Vol. V. 



Color olivaceous, some specimens blotched with black; others with 

 1 to 3 black spots about % size of the eye on the sides; occasional 

 specimens with a large black blotch on side behind shoulders; some 

 with a large black spot at base of caudal fin ; this spot very small in 

 others and in some specimens wanting ; a broad black crescent on base 

 of caudal rays; often the spot or crescent or both wanting; occa- 

 sionally these markings reduced to the tips of the crescent or to the 

 base of marginal rays of the caudal fin ; dorsal fin black ; anal and ven- 

 tral rays with black tips; pectorals light. Length about 1^ inches. 



The color markings of this species are very variable, more so than 

 of any other species I have examined. 



136. Platypcecilus variatus sp. nov. 



Type, No. 4501, F. C. M., 1.35 inches in length; Valles, San Luis 

 Potosi. 



Basins of the Rio Panuco and Rio Soto la Marina, in owland 

 streams. (Garza Valdez; Santa Engracia; Victoria; Forlon; Valles; 

 Rascon.) 



Head 3^; depth 2^ to 2^; D. 10; A. 6 or 7 ; scales 9-25. Body 

 oblong, compressed ; profile from front of dorsal to tip of snout slightly 

 convex, the highest point at origin of dorsal fin; interorbital area flat, 

 its width 2 in head; lower jaw slightly the longer; eye 2^2 in head; 

 snout 4 in head; teeth loose, conical, in a single series; dorsal fin in 

 advance of anal, its origin midway between base of caudal and pupil ; 

 longest dorsal ray in both sexes, 1^ in head; caudal peduncle mod- 

 erately compressed, its least depth 5 in length of the body; distance 

 from last dorsal ray to base of caudal y$ greater than least depth of 

 caudal peduncle; caudal fin slightly rounded; anal fin with a slightly 

 convex margin; longest anal ray (in ?) i^in head; tips of pectorals 

 reaching slightly past base of ventrals; length of pectoral fin ii in 

 head; tips of ventrals reaching origin of anal, if in head; alimentary 

 canal coiled on right side as in the preceding species; gill rakers 

 1 5 , the longest equaling diameter of pupil ; vertebrse 14+14 = 28; anal 

 fin modified into an intromittent organ, its length if in the head. 



Color olivaceous, the upper half or two-thirds of the body much 

 mottled with darker; some specimens with a black caudal spot, in 

 some specimens large, in others very small. Length about 2 inches. 



The color markings of this species vary greatly. The black cres- 

 cent and the black caudal spot may both be present or one or the 

 other or both may be absent. One large male, the largest taken, 

 1.87 inches, has four distinct black vertical bars on the middle of the 

 sides of the body; it also has the black blotch and crescent at base of 

 caudal fin; a second large male (1.70 inches), has the black bars on 



