88 FIELD COLUMBIAN MUSEUM ZOOLOGY, VOL. III. 



ous. Either all of their specimens were females or they overlooked 

 this peculiar modification of the anal fin of the male. The spawning 

 time of all the species of this family in Mexico is near the close of the 

 dry season. 



Mr. Mcenkhaus informs me that he has taken young from the 

 females of several species of Cyprinodonts in Brazil. It is quite cer- 

 tain that viviparity is far more characteristic of this family than has 

 been generally supposed. 



I append here a key to the genera of Pa'ciliida. It is practically 

 the one given by Jordan and Evermann in "Fishes of North and 

 Middle America," though revised to include the new genera proposed 

 in this paper. 



KEY TO THE GENERA OF P(KCILI1D^. 



a. Intestinal canal comparatively short, little convoluted, usually 

 less than one and one-half times the total length of the body (2 in 

 Chapalichthys); teeth little movable; dentary bones firmly united. 

 Species chiefly carnivorous. 



/>. Outer series of teeth enlarged, pointed or a few of the ante- 

 rior ones compressed, incisor like: none of them notched, bicuspid or 

 tricuspid. 



c. Anal fin of the male similar to that of the female, not modi- 

 fied by having its five or six anterior rays short and stiff, and sep- 

 arated at their tip from rest of the fin by a notch, and not modified 

 into a sword shaped intromittent organ. Species oviparous. 



(1. Ventral fins wanting; pharyngeal bones both above and 

 below greatly enlarged, bearing coarse blunt teeth: scales normal. 

 (Orestiinae). KMPKTRICHTHVS. 



dd. Ventral fins well developed: pharyngeal bones and teeth not 

 enlarged. (Funclulime.) 



e. Teeth in more than one series, usually a larger outer series, 

 behind which is a band of smaller teeth. 



f. Air bladder well developed (in all species examined): no cau- 

 dal ocellus: body oblong: dorsal fin various in size and insertion. 



FUNDULUS. 



//. Air bladder wanting: a black ocellus at root of caudal (at 

 least in the males). KIYTLUS. 



cc. Teeth arranged in a single series: dorsal fin inserted in 

 advance of anal, its rays 9 to 13. I.UCAMA. 



cc. Anal fin of the male with its first five or six rays short and 

 stiff, and slightly separated from the rest of the fin by a notch. Spe- 

 cies viviparous, the young usually of large size at birth. 



