460 MEMOIRS OF THE CARNEGIE MUSEUM 



In life, sides of male yellowish, caudal peduncle pokeberry-red to dark olive- 

 green; upper caudal prong bordered by pokeberry-red below, or rusty; one male 

 with a black streak and a milk-white margin to the anal. 



Subfamily Tomeurin^e. 



Tomeurus Eigenmann. 

 Tomeurus Eigenmann, Ann. Carnegie Mus., VI, 1909, 53. 



Teeth conical, in about three series; dorsal placed far back over the last fourth 

 of the body; anal in the female in advance of the middle of the body, in the 

 male moved forward to below the origin of the pectorals; ventrals not evident 

 in the female, minute, under the upper angle of the gill-opening, in the male; 

 pectorals large; alimentary canal much shorter than the body; caudal peduncle 

 with a ventral knife-like ridge extending almost its entire length, resembling 

 an adipose fin, but composed of about sixteen paired scales; intromittent 

 organ of the male very long, composed of the first three anal rays, the first divided 

 into two lateral prongs near the tip, each of which has a backward projecting pro- 

 cess near its middle and a slender spine-bearing appendage near its base; a similar 

 but larger spine-bearing appendage between the bases of the prongs. 



307. Tomeurus gracilis Eigenmann. (Plate LXV, figs. 7, 8.) 

 Tomeurus gracilis Eigenmann, Ann. Carnegie Mus., VI, 1909, 53; Repts. Princeton 



Univ. Exp. Patagonia, III, 1910, 461. 



Type, 31 mm. (Carnegie Museum Catalog of Fishes No. 1093.) 



Cotypes, three males, 29-30 mm. Mud creek in Aruka River. 



Cotypes, three females, about 20, 24, and 28 mm. Mud creek in Aruka 

 River. (C. M. Cat. No. 1094; I. U. Cat, No. 12076.) 



Cotype, one female, 18 mm. Wismar. (C. M. Cat. No. 1095.) 



This species represents the type of a new subfamily of Pceciliids. 



Head 5.5; depth 6.5; D. 6; A. 6; scales 39 from occiput to tail, seven between 

 the middorsal scale and the ventral ridge; twenty-six scales in front of the dorsal; 

 eye longer than snout, 3.75 in head, a little less than the interorbital. 



Very long and slender; mouth rather large, vertical, its width equal to the 

 diameter of the eye; origin of dorsal near beginning of the third fourth of the length, 

 its height equal to length of head less opercle; caudal rather pointed, 3.5 in the 

 length; origin of anal a little in advance of the middle, small; intromittent organ 

 of the male one-third of the length, its origin a little in advance of the vertical 

 from the base of the pectoral, extending to the ventral ridge; pectorals equal to 

 their distance from the snout. 



