THE CYPRINODONTS. 139 



chen besetzt, zuweilen auch die Caudale. Die iibrigen Flossen stets unge- 

 fleckt ; Caudale am hiiiteren Rande zuweilen (bei Mannchen) breit, weisslich 

 gesfiumt und in der vorderen Hitlfte stets dicht iiberschuppt. 35-36 Schup- 

 pen zwischen dem oberen Eude der Kiemenspalte und dem Beginne der 

 Caudale in einer Lixngsreibe und 11^ zwischen der Mittellinie des Eiickens 

 und der Basis des ausseren Ventralstrables in einer Querreihe. 



Cauca. (Steind.) 



Closely allied to B. micropus, of which it may yet prove to be a variety. 



Rivulus ornatus sp. n. 



B. 6-5; D. 6; A. 10-11; V. 6 ; P. 12-14; LI. 31; Ltr. 8. 



Shaped like the majority of the species in the genus. Head one fourth 

 of the length to the base of the caudal, broad, flattened on the crown, de- 

 pressed. Snout broad, rounded, about as long as the eye. Eye one fourth 

 of the head, one half of the interorbital space. First ray of dorsal above 

 last of anal, two thirds of the distance from the base of the pectoral to the 

 base of the caudal, or three fourths of that from the front edge of the eye 

 to the caudal. First ray of anal half way from head to base of caudal. Van. 

 trals small, not reaching the anal. Pectorals elongate, as long as the head, 

 reaching nearly to the ventrals. Caudal elongate, pointed. 



The markings of this fish are made up of puncticulations ; they form 

 transverse blotches along the back, streaks along the sides, series of dots 

 across the fins, a dark band on the lower lip, and a dark streak backward 

 from below each eye. In cases light bands on the back meet dark vertical 

 bars on the flank. Some specimens are dark brownish, others very light. A 

 few are quite dark on the back. The longest measure one and three eighths 

 inches. 



Silva ; Cudajas ; Lago Alexo ; Lake Hyanuary. 



The formula D. 6 ; A. 8 ; P. 12 ; LI. 26; Ltr. 6, is taken from an indi- 

 vidual resembling the preceding in position of dorsal and anal, but lacking 

 the blotches and bearing a streak from occiput to caudal and another from 

 anal to caudal. Other collections may prove this to belong to a distinct 

 species. It was obtained in Lago Alexo. 



