THE CYPRINODONTS. 91 



Heterandria formosa. 



Plate IV. Fig. 7, teeth; Plate VIII. Fig. 8; Plate XI. Fig. 1-3. 



Heterandria formosa Agassiz, 1855, Am. Jour., XIX, 136 ; Gid., 1859, P. Phil. Ac, 62 ; Jor. & M., 1885, 

 P. U. S. Mus., VII, 236 ; Jor., 1SS7, R. U. S. F. Com., 838; Heusli., 1891, B. U. S. F. Com., IX, 374. 



Girardima furmoms Grd., 1859, P. Phil. Ac, 62 ; Blk., 1860, Cypr., 484 ; Put., 1863, B. M. C. Z., 14; 

 Gthr., 1866, Cat, VI, 354 ; Jor. & C, 1877, B. Buf. Soc, III, 142 ; Jor., 1878, B. U. S. G. Sur., IV, 434 ; 

 Goode, 18S0, P. U. S. Mus., II, 119 ; Jor. & G., 1882, B. 16 U. S. Mus., 349. 



Gambiisia formosa Blk,, 1800, Cjpr., 485. 



Htidrargyra formosa Blk., 1860, Cypr., 486. 



Heterandria (= Qirardinus) formosa Jor., 1885, P. U. S. Mus., VII, 323. 



Heterandria ommata Jor., 1885, P. U. S. Mus., VII, 323,-1887, R. U. S. F. Com., 838 ; Bean, 1886, 

 P. U. S. Mus., VIII, 555 ; Woolm., 1892, B. U. S. F. Com., X, 302. 



Zi/gonectes Muiiiii Hay, 1885, P. U. S. Mus., VIII, 555. 



Rivulus ommatus Jor., 1887, P. U. S. Mus., IX, 527. 



B. 5 ; D. 7-8 ; A. 10-11 ; V. 6 ; P. 12 ; LI. 27-31 ; Ltr. 7-8 ; Vert. 

 14 + 18. 



Moderately compres.sed, caudal pedicel moderately stout. Head flattened 

 on the crown, about equal depth of body or one fourth of the distance from 

 snout to base of caudal. Snout short, half as long as the eye, narrow, blunt. 

 Mouth small, directed upward, very protractile ; lower jaws longer, firmly 

 united ; ujDper short. Chin steep. Teeth in bands, outer series longest, 

 slender, firmly set, slightly compressed and expanded near the acuminate 

 point. Eye large, nearly twice the snout, once the interorbital space, or 

 one third of the head. Dorsal fin smaller than anal. In females these fins 

 are opposed, the former originating near the middle of the total length and 

 slightly backward of the latter. On males, dorsal, anal, and ventrals are 

 farther forward, the last two resting below the pectorals, while the anterior 

 rays of the anal form a very elongate pointed intromittent organ, one third . 

 of the total length of the fish. Pectorals small. Caudal broad, rounded. 

 Intestine about equal length of body, without head or caudal. In females of 

 less than an inch in length the young are about ready for birth. 



Olivaceous to yellowish, lighter to silver or yellow below, with an indefi- 

 nitely margined band of blackish from tip of snout to caudal base along the 

 middle of the flank, and most often with eight to fifteen vertical bars or 

 blotches of blackish crossing the longitudinal band, which commonly ends in 

 a black spot at the base of the tail. The vertical bars are generally inter- 

 rupted on the back, but may be continuous ; frequently they are less intense 

 immediately above the dark band on the flank. Many specimens are darker 

 on the edges of the scales. The dorsal is occasionally tipped with black ; 

 usually it has a black spot with or without white edges on its base. Most of 



