MARINE PROVINCES. 



113 



M. d'Orbigny's list also includes the following genera : — 



Octopus. Lyonsia. Solen. Corbula. 



Columbella. Solecurtus. Lutraria. Pinna. 



BuUia. JEolis. Donacilla. Mytilus. 



Pleurotoma. Paludestrina. Nucula. Lithodomus. 



Fissurellidsea. Scalaria. Leda. Pecten. 



Panopgea. Natica. Cytherea. Ostrea. 



Periploma. , Chiton. Petricola. 



XVII. Caribbean Province. 



The Gulf of Mexico, the West Indian Islands, and the eastern 

 coast of South America, as far as Rio, form the fourth great 

 tropical region of marine life. The number of shells is estimated 

 by Prof. C. B. Adams at not less than 1500 species, which is 

 certainly an under-estimate. Of these 500 are described by M. 

 d'Orbignj^ in Ramon de la Sagra's History of Cuba, and a small 

 number of the Brazilian species in the same author's Travels in 

 South America. 



The coasts of the Antilles, Bermuda, and Brazil, are fringed with 

 coral reefs, which attain their greatest development around the 

 Bahamas, South of Florida, north of Cuba and at the Bermudas; 

 and there are considerable banks of gulf-weed at some distance 

 from the coast of the Antilles. The peculiar fauna of the coral 

 reefs is therefore represented in the West Indies, but without 

 the richness of zoological forms which characterizes it in the 

 Indo-Pacific province. 



The discovery of representatives of ancient genera once 

 supposed to be extinct gives a peculiar interest to this Province. 

 Such are Pholadomya, Pleurotomaria, and Murchisonia. The 

 group Melongena belongs to this fauna and the neighboring 

 Panamic province exclusively, although anciently extending to 

 Europe. 



The Caribbfean fauna contains a large number of species 

 common to the West coast of Africa and to Panama ; Dolium 

 galea of the Mediterranean Sea is also found here. But the most 

 remarkable circumstance is the presence of a number of Indo- 

 Pacific forms, including a dozen species of Triton. 



XYIII. Transatlantic Province. 



The Atlantic coast of the United States was supposed by 

 Prof. E. Forbes to consist of two provinces : (1) The Virginian.^ 

 from C. Cod to C. Hatteras and (2) the Carolinian, extending 

 to Florida ; but no data were supplied for such a division, and 

 the distribution of the shells does not warrant it. The total 

 number of mollusca is about 300, and 60 of these range farther 



