XVIII. — Observations on Different Points of the Natural History 

 of the Island of Cuba, with reference to the Ichthyology of the 

 United States. 



By Felipe Poet, of Havana, Cuba, Corresponding Member. 

 Read Sept. 18, 1854. 



I have described in my Memorias sobre la Historia Natural 

 de la Isla de Cuba, Vol. i., page 374, several fish belonging to 

 the family of the Cyprinoids, of the division which M. Agassiz 

 has named Cyprinodonts, from their jaws being furnished with 

 teeth. These species are allied to the genera Poecilia, Mollinesia, 

 and Hydrargyra, but differ sufficiently to prevent their being 

 placed in any one of them. This obliged me to establish the 

 genera Gambusia, Girardinus, and Limia, described in the above 

 "Memorias." One remarkable peculiarity of all these Cypri- 

 noids of Cuba is to be found in the anal fin of the males, which 

 is always formed as shown by figures 31 and 32 of the work 

 above referred to, besides which the males are one- third smaller 

 than the females. This fin studied with care shows constantly 

 11 rays, of which the 3d, 4th, and 5th are always the stoutest. 



In the classic work of Messrs. Cuvier & Valenciennes, the 

 genus Poecilia has seven species from equinoctial America ; of 

 which 4 are from South, 2 from Central America, and 1 from 

 Hayti. The genus Mollinesia (Mollienisia) has but one single 

 species, the M. latipinna of the southern U. States. The 

 genus Hydrargyra is composed of three species from the U". 

 States, and one from Spain. M. Valenciennes does not dis- 

 tinguish the sexes of the Pcecilias nor of the Hydrargyras, 

 which would lead me to believe that he has only seen females : 

 he has, on the contrary, only seen one male of Mollinesia in which 

 the anal fin greatly resembles the anal of my Cuban genera. 

 Dr. Storer does not allude to the sexual differences. I have not 



OCTOBER, 1855. 10 Ann. Ltc. Nat. Hist. Vol. VI. 



