Family XI. Pceciliid^. 127 



small, terminal, interorbital slightly convex, 2^ in head; eye small, 

 equaling the length of the snout. 3^3 in head; origin of dorsal fin mid- 

 way between base of caudal and anterior margin of orbit; base of 

 dorsal 2 in head; pectoral i 1 /^ in head; ventral 3 in head; caudal fin 

 rounded; least depth of caudal peduncle 1% in head. 



Color of adult males very dark to light brownish; caudal fin plain 

 with a narrow black band at tip; ventrals and anal plain, tipped with 

 black; dorsal fin dark; females are much lighter, the larger ones much 

 speckled with small dark dots; faint dark bands on middle of side 

 along rows of scales; a black blotch on last rays of dorsal and a;nal; 

 the smaller females more or less blotched with darker, but much less 

 than in the preceding species. Length about 2.55 inches. The fe- 

 males taken are full of quite mature eggs. 



The specimens from Labor average larger than those taken in the 

 river at Durango. Professor Garman gives dorsal rays 12; anal rays 

 11. No doubt he counted the rudiments as well. There is some 

 doubt as to whether or not Prof. Garman's specimens really came from 

 Parras, Coahuila I am inclined to believe the types of this species, 

 also the types of Characodon garmani Jordan & Evermann came from 

 near Durango. 



Subfamily Gambusiinae. 



51. Pseudoxiphophorus Bleeker. 



Pscudoxiphophorus Bleeker, Irhthyol. Ind. Prod. Cupr., 483, i860. 

 (Type, Xiphophorus bimaculatus Heckel.) 



Precilioides Steindachner, Sitzgsber. Akad. Wiss. Wien, 1863, 176. 

 (Type. Xiphophorus bimaculatus Heckel.) 



Body elongate, robust; head flat, depressed forward; dorsal fin 

 long, its base about one-half longer than head; anal fin of male 

 modified into an intromittent organ; teeth conical, in a band on each 

 jaw, the outer series enlarged; gill rakers short and stiff, about 16 on 

 first arch those on upper portion of the arch trie longer; alimentary 

 canal short, less than the length of the body; vertebrae 18 + 14 =32. 

 One species known, viviparous. 



117. Pseudoxiphophorus bimaculatus (HeckeP. 



Xiphophorus bimaculatus Heckel, Sitz. Akad. Wiss. Wien, 1848, 

 196; Mexico. 



Pseudoxiphophorus bimaculatus Gimther, Cat., vi, 333, 1866: Gar- 

 man, Memoirs, Mus. Comp. Zool., xix, 1895, 81, pi. 111, fig. 6 

 (teeth), pi. viii, fig. 9 (male) ; Mexico : Woolman, Bull. U. S. Fish 

 Comm. 1894, 65; Rio Blanca, Orizaba: Jordan & Evermann, 



