82 THE CYPRINODONTS. 



cases the scales have a wide posterior edging of black. On some the 

 median row on the flank has a wide black tip. A dark patch behind the 

 eye is common, as, also, the black blotch on the upper half of the base of 

 the caudal. Occasionally a small whitish spot appears on the middle of the 

 scale. Fins dusky to almost black ; caudal with or without a light trans- 

 verse streak behind the black blotch. On very dark colored individuals the 

 caudal is nearly black and the blotch is indistinct. 



Attaining a length of four inches. 



Mexico. 



GAMBUSIA. 



Gamhusia Poey, 1855, Mem., I, 382, 390,-1861, Mem., II, 383,-1868, Repert., II, 209,410; 

 Gtlj., 1866, Cat., VI, 333, — 1880, Intr., 616 ; Jor. & G., 1882, B, 16 U. S. Mus., 341. 

 Qambusibia Gill, 1894, Mem. Nat. Acad., VI, 133. 



Body rather short and stout ; caudal pedicel deep ; head depressed. 

 Snout broad, blunt. Chin moderately steep. Mouth large, wide, resem- 

 bling that of Zygonectes ; mandibles strong, firmly united ; intermaxillaries 

 shorter, protractile. Teeth conical, in cards, hooked, outer series larger. 

 Branchiostegal rays usually six. Dorsal originating behind the middle of 

 the body ; anal origin farther forward, fin more advanced and modified 

 to form an intromittent organ in the male. Intestine rather short. 



The separation of this genus from Heterandria seems to be fully war- 

 ranted by the sliape of the teeth, the structure of the mouth, the number 

 of branchiostegal rays, and other particulars. Unless otherwise specified the 

 species are described from females. 



Gambusia Holbrookii. 



Plate IV. Fig. 3, teeth; Plate VIII. Fig 5; Plate XI. Pig. 4-13. 



Heterandria Holbrookii (Ag.) Grd., 1859, P. Phil. Ac., 61. 



Gamhisia Holbrookii, Blk., 1860, Cypr., 485 ; Put., 1863, B. M. C. Z., 14 ; Gth., 1866, Cat., VI, 334 ; 

 Goode, 1880, P. U. S. Mus., II, 118. 



Oambusia patruelis Jor., 1881, P. U. S. Mus., Ill, 21,-1885, P. U. S. Mus., VII, 322; Ryder, 1882, 

 Amer. Nat., Feb., — 1886, P. U. S. Mus., VIII, 143, pi. 6-10; Jor. & G., 1882, B. 16 U. S. Mus., 893,— 

 1887, P. U. S. Mus., IX, 26 ; Jor. & M., 1885, P. U. S. Mus., VII, 235 ; Gilb., 1890, B. U. S. P. Com., ^ 

 228,-1891, B. U. S. F. Com., IX, 158 ; Hensh., 1891, B. U. S. F. Com., IX, 374; Bean, 1892, P. U. S. 

 Mus., XIV, 92 ; Smith, 1892, B. U. S. F. Com., X, 69. pi. 20, fi,<^. 1 ; Wonlm., 1892, B. U. S. F. Com., X, 

 294, 296, 298, 300, 301. 



Gambusia patruelis holbrookii Jor. & G., 1883, P. U. S. Mus., V, 587. 



Haplochilus wclanops Cope, 1870-77, P. Am. Phil. See, XI, 457. 



Zygonectes melanops Jor., 1876, Man. Vert., 252 ; Jor. & C, 1877, B. Buf. See, III, 142. 



Zygonectes {Micristius) melanops Jor., 1878, Man, Vert, 264, — B. U. S. G. Sur., IV, 433 ; Jor. & G., 

 1882, B. 16 U. S. Mus., 340. 



Zygonectes alrilatus Jor. & B., 1878, B. 12 U. S. Mus., 84 ; Jor. & G., 1883, P. U. S. Mus., V, 258. 



Zygonectes {Micristiiis) utrilatus Jor. >t G., 1882, B. 16 U. S. Mus , 340. 



