330 FIELD MUSEUM OP NATURAL HISTORY ZOOLOGY, VOL. X. 



anal of female small, its third ray the longest; modified anal of male 

 shorter than the head; ventrals small, not reaching anal; caudal deep, its 

 posterior margin rounded. 



Color brownish, bases of scales dark; dorsal region dark, the ventral 

 region silvery; dorsal with one to several transverse series of small spots 

 of black, the fin sometimes black tipped; caudal with small spots of 

 black on basal half, or with a couple of clouded transverse bands; the 

 fins uniform or punctulate. (Garman.) 



This species was not seen by us. 



66. Mollienisia formosa (Girard). 



Limia formosa Girard, Proc. Ac. Nat. Sci. Phila., 1859, 115 (Palo Alto, 



Mexico). 

 Mollienisia formosa Gunther, Cat. Fish. Brit. Mus., VI, 1866, 349; 



Jordan & Evermann, Bull. U. S. Nat. Mus., XLVII, 1896, 699; 



Regan, Proc. Zool. Soc. Lond., 1913, 1012 (Tampico, Mexico; Colon, 



Panama). 



Head 3.3 to 4; depth 2.5 to 3; D. u to 14; A. 9 or 10; scales 26 to 28. 



Body rather robust; eye 3 to 3.5 in head; interorbital 1.7 to 2; origin 

 of dorsal a little nearer the base of caudal than the end of the snout; 

 origin of anal below fourth ray of dorsal; pectoral shorter than the head; 

 caudal fin rounded; least depth of caudal peduncle, 1.3 to 1.6 in head; 

 modified anal of male 1.3 in head. 



Color olivaceous; scales with brown spots; dorsal fin with transverse 

 series of blackish spots, other fins plain. 



This species is recorded from Colon by Regan. It does not occur in 

 our collections. 



Habitat: Atlantic slope of Mexico and Central America. 



42. Genus Rivulus Poey. 



Rivulus Poey, Memorias, II, 1858, 307 & 383 (type Rivulus cylindraceus 



Poey). 

 Cynodonichthys Meek, Field Col. Mus. Pub., Zool Ser., V, 1904, 101 



(type Cynodonichthys tenuis Meek). 



Slender fishes with subterete body; mouth small, the branches of the 

 lower jaw firmly united; teeth conical, in bands, the outer ones enlarged 

 and curved; one or two teeth on each side usually enlarged and canine- 

 like; margin of eyes not free; pectorals obtuse, low; caudal rounded or 

 subtruncate; dorsal small, over posterior part of the much longer anal; 

 oviparous; air bladder large; alimentary canal short, about % to & 

 length of body. 



