360 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1937 



Puerto Rico is tho most remarkable of the Greater Antilles. In spite 

 of the fact that its higher vertebrate fauna is very comparable to that 

 of Hispaniola, its sole and only fresh-water fish is the viviparous 

 cyprinodont Foecilia vivipara, which is common in South America 

 and the Leeward Islands. That this strange absence of anything we 

 might expect is real and not merely apparent is shown by Dr. Hilde- 

 brand's recent extensive survey of the Puerto Rican streams. ^^ I am 

 strongly of the opinion that the Poecilia got there by fortuitous means, 

 or by the hand of man. Many years ago Cuvier and Valenciennes 

 described a Fundulus from Puerto Rico, but it has remained known 

 from tho single type specimen in Paris, since the other type specimens 

 were shown to be a GamhiLsia. I do not believe that a Fundulus 

 exists in the island. Where Nichols (1929) got his figure of it I cannot 

 say. 



WHAT DO THE ANTILLEAN FRESH-WATER FISHES INDICATE? 



It is difficult to say just what the fishes indicate. The distribution 

 of several of them is so peculiar as to suggest that their arrival has 

 been fortuitous and not dependent on dry-land connections. Mollieni- 

 sia in Hispaniola, Poecilia in Puerto Rico and the Leewards, and 

 Cubanichthys in Cuba are examples in point. The arrival of one 

 Limia in Cuba and the presence of scarcely different cichlids in Cuba 

 and Hispaniola might signify ocean navigation by these fishes, and I 

 think this not unlikely. However, the presence of girardinine 

 poeciliids in Cuba, their absence in Hispaniola and Jamaica, and the 

 close relationships of the Gambusias and Limias of the last two islands 

 is instructive. I do not think Cuba and Hispaniola have been united 

 during the probably long existence of the girardinines, but Jamaica 

 and Hispaniola may have been. Puerto Rico, from the fish evidence, 

 seems to have had a long separate history. 



Of course the most remarkable thing of all is the entire absence of 

 Ostariophysi in the West Indies. On the face of it, the fish evidence 

 therefore points strongly toward a lack of any mainland connection 

 during a considerable part of the Tertiary. Personally, I am of the 

 opinion that some northern and a number of southern Ostariophysi 

 have been in the process of penetration of Central America for a long 

 time, and that their absence in the islands is significant. But another 

 alternative must not be lost sight of. Scharff, Schmidt, and others 

 have mentioned the fact that the land area available seems to have a 

 direct bearing on the survival of at least parts of a land fauna — in 

 other words that an island, thi'ough partial submergence, might become 

 too small to permit the survival of certain species. I do not at the 

 moment recall having seen this idea applied to the fresh-water fishes 

 of islands, and I think it will repay us to digress a bit to discuss it. 



i«HUdebrand(1935). 



