NATURAL SCIENCES OF PHILADELPHIA. 61 



the bands themselves. The fins are greyish olive, unieolor ; the anal and the 

 ventrals, in the female, being oftentimes of a lighter tint. 



In allusion to the numerous transverse lateral bars, we shall call this species 

 Hydrargyra zebra. 



XL In 1853, (Amer. Journ. of Sci. and Arts, second series, xvi. 135), the 

 genus Heterandria was proposed to include two small species of fish inhabiting 

 the fresh water ditches of South Carolina. All that we were told about their 

 generical characters had reference to the anal fin, which in the male sex, is very- 

 slender and deep and inserted more anteriorly than in the female. That dif- 

 ference between the sexes suggested the appellation of Heterandria. Most 

 genera of the so called Cyprinodonts, however, exhibit similar sexual dif- 

 ferences in a greater or lesser degree. 



In the same year, 1853, we described four species under the head of Heteran- 

 dria, three of which we have recently* referred to the genus Gambusia, and one 

 to the genus Girardinus, proposed by Prof. Poey, of Havana, to include sundry 

 Cuban species. The genus Limia, of the same author, would likewise fall 

 under the head of Heterandria, as indicated. The genera just alluded to of the 

 Cuban naturalist, not only cover the same ground as Heterandria, but have 

 priority over the latter. 



The following characters may be assigned to the genus Gambusia. Mouth 

 protractile, rather cleft and nearly horizontal, the lower jaw projecting some- 

 what beyond the upper. An external series of rather conical, curved and 

 conspicuous teeth, behind which may be observed a patch of velvet like teeth. 

 The origin of the anal fin is situated in advance of the anterior margin of the 

 dorsal, deeper and differently constructed in the male than in the female. 

 The branchiostegal rays numbering six on either side ; the branchial orifices 

 being continuous under the throat. Prof. Poey states that the intestine is 

 short, and the liver large, t 



Amongst the fishes recently collected by Mr. T. Glover, at Palatka, East 

 Florida, we find specimens of a species of Gambusia, which upon comparison 

 with the specimens of Heterandria kolbrookii, Ag. (MS.) collected by ourselves 

 in Charleston, S. C, prove to be identical with the latter. 



The largest female specimen which has come under our observation, mea- 

 sures two inches in total length, in which the head enters four times and a 

 half, and the caudal fin six and a half times. The head itself is very much 

 depressed and sloping towards the snout, giving the latter a wedge-shaped ap- 

 pearance, a trait not altogether peculiar to the species of this genus, for we 

 observe it in Pacilia, Limia, Girardinus, and to a certain degree in Fundulus 

 and Hydrargyra. The eye is very large, subcircular ; its diameter entering but 

 three times and a half in the length of the side of the head. The body is sub- 

 fusiform in profile when not otherwise distorted by the presence of ova or 

 embryos in the abdomen. The origin of the dorsal fin is much nearer the 

 extremity of the caudal than the tip of the snout ; the fin itself being 

 higher than long. The anal fin is larger than the dorsal, deeper than long, 

 exteriorly subtruncated, its anterior margin being nearly equidistant between 

 the tip of the snout and the extremity of the caudal fin. The ventrals are 

 small, short and broad when expanded ; their tips extending as far as the 

 vent when the belly is not otherwise distended. The pectoral fins are rather 

 large, projecting beyond the insertion of the ventrals when in their natural 

 condition. The formula of the fins is as follows : D8; A 9 ; C 4, 1, 6 6 1 

 5 ; V 6 ; PI, 10. 



The largest male specimen which we have examined, measures about an 

 inch and a quarter. The body is quite slender, and fusiform in profile, the 

 head holding the same proportions towards the total length as in the female 



* U. S. and Mex. Boundary Report, vol ii. Ichthyology, pp. 71 and 73. 

 f Memorias sobre la Historia Natural de la isla de Cuba, i. 1851, 390. 



1859.] 5 



