44 THE CYPRINODONTS. 



the support of the anal fin, Plate VIII. Fig. 16. Intestine elongate. Type, 

 C. decemmaciilatus from the Uruguay River. 



Cnesterodon decemmaculatus. 



Plate V. Fig. 13, teeth ; Plate Vlll. Fig. 16, male. 



Pcecilia decemmacula/us Jeu., 1842, Zool. Beagle, Fish, 115, pi. 22, fig. 1 ; Blk., 1860, Cypr., 486 ; Eig., 

 1894, Anu. N. Y. Ac, VII, 637. 



Pcecilia gracilis Val., 1846, C.V. Poiss., XVIII, 133 ; Blk., 1860, Cypr,, 486. 



airardiiius decemmaculatus Gth., 1866, Cat., VI, 355; Heus., 1868, Arch. f. Nat., XXXIV, 364, — 

 1869, XXXV, 89 ; Perug., 1891, Aim. Mus. Civ. Gen., X (2), 653; Eig., 1891, P. U. S. Mus., XIV, 65. 



B. 5 ; D. 8 ; A. 10-9 ; V. 6 ; P. 12 ; LI. 31 ; Ltr. 8-9 ; Vert. 14+18. 



This is evidently a small species ; females of one and one eighth 

 inches bear well developed young. The shape of the body bears some 

 likeness to that of Heterandria formosa, on Plate XI. The length of the 

 head is equal to the depth of the body, and is four fifteenths of the 

 distance from snout to base of caudal. Crown slightly arched trans- 

 versely. Snout short, about three fifths of the eye, broad, blunt. Mouth 

 moderately wide, opening upward ; lower jaws longer, somewhat firmly 

 joined ; i;pper short, protractile. Outer series of teeth rather broad and 

 shovel-shaped, hooked ; inner in a band, not numerous, very small, pointed, 

 apparently with a slight expansion at each side near the apex ; pha- 

 ryngeal slender, hooked. Eye large, longer than snout, two fifths of head, 

 three fourths of forehead. Dorsal origin nearly midway from eye to base 

 of caudal, about opposite that of anal. On males the anal is farther for- 

 ward, and modified into a long intromittent organ. On the specimen ex- 

 amined this organ is bladelike and without hooks, about one and one half 

 times the length of the head or less than half as long as head and body with- 

 out the caudal. Ventrals very small, rays sometimes five. Pectorals reach- 

 ing the middle of the ventrals. Caudal elongate, deep, convex. Scales large, 

 twelve between occiput and dorsal. 



Light olivaceous, cheeks and throat silvery, belly silvery to golden. A 

 series of irregular, more or less indistinct spots of dark color betweefn the 

 upper angle of the gill-opening and the middle of the caudal. Edges of 

 scales darker. Tip of caudal sometimes darker. Some have a narrow streak 

 of dark color on the middle of the caudal pedicel. In cases dorsal and anal 

 are darker near their extremities. 



Uruguay River ; Maldonado. 



