28 U.S. NATIONAL MUSEUM BULLETIN 292 



The Ocypodidae : Wliile this family is represented in the West 

 Indies by 10 species, only one, Uca burgersi, is endemic. This species is 

 closely related to U. mordax, which is known with certainty to occur 

 only along the northern coast of South America. Until the ranges of 

 the two are better understood, no hypotheses concerning the possible 

 origin of U. burgersi can be offered. 



Uca cumulanta is a South American species that has become estab- 

 lished on Curasao but has not been reported from other islands 

 in the Lesser Antilles or from those considered herein as the Caribbean 

 islands. A third species, JJ. speciosa, which is known to be present in 

 Yucatan, Cuba, Jamaica, and Florida probably had its origin in the 

 Central American-Mexican region and migrated to the Greater 

 Antilles and Florida. Whether or not it reached Florida by way of 

 Jamaica and Cuba can only be left to conjecture. The homogeneity 

 of its characters suggests a Pleistocene or recent invasion of the 

 islands and Florida. 



The remaining representatives of the family are widely spread on 

 the adjacent continents, and there are no data to indicate from what 

 area or areas the insular members were derived. 



Other families: The following families are not treated in this discus- 

 sion largely because the mde ranges of the species composing them 

 provide little or no data concerning the origins of their members: 

 Penaeidae, Hippolj^tidae, Porcellanidae, Coenobitidae, Portunidae, 

 Xanthidae, and Gecarcinidae. 



Endemism and origin. — The following is a summary of our tenta- 

 tive conclusions concerning the source of the several freshwater or 

 landlocked decapod stocks that have invaded the West Indies, to- 

 gether with estimates of the probable time of their island invasion 

 (numbers in parentheses indicate species endemic to the West Indian 

 region) : 



Number of species in 

 Ancestors of— West Indies Probable time of invasion 



(from the Central American-Mexican 

 Region) 



Jonga 1 (0) Recent 



Micraiya 1 (0) Recent 



Potimirim 2 (0) Pleistocene or Recent 



Typhlatya 3 (2) Tertiary 



Macrobrachium 6 (1) ? 



Procambarus 3 (3) Tertiary 



Epilobocera 7 (7) Tertiary 



Pseudothclphusa 3 (1) ? 



Glyptograpsus 1 (1) Tertiary 



{?)Sesarma 3 (3) Tertiary 



(?)Metopaulias 1 (1) Tertiary 



