62 ZOOLOGICAL GEOGRAPHY. [part in. 



history, and will enable us to account for much that is peculiar 

 in the general character of their natural productions. 



If we draw a line immediately south of St. Croix and St. 

 Bartholomew, we shall divide the Archipelago into two very 

 different groups. The southern range of islands, or the Lesser 

 Antilles, are, almost without exception, volcanic ; beginning with 

 the small detached volcanoes of Saba and St. Eustatius, and 

 ending with the old volcano of Grenada. Barbuda and Antigua 

 are low islands of Tertiary or recent formation, connected with 

 the volcanic islands by a submerged bank at no great depth. 

 The islands to the north and west are none of them volcanic ; 

 many are very large, and these have all a central nucleus of 

 ancient or granitic rocks. We must also note, that the channels 

 between these islands are not of excessive depth, and that their 

 outlines, as well as the direction of their mountain ranges, 

 point to a former union. Thus, the northern range of Hayti is 

 continued westward in Cuba, and eastward in Portorico ; while 

 the south-western peninsula extends in a direct line towards 

 Jamaica, the depth between them being 600 fathoms. Between 

 Portorico and Hayti there is only 250 fathoms; while close to 

 the south of all these islands the sea is enormously deep, from 

 more than 1,000 fathoms south of Cuba and Jamaica, to 2,000 

 south of Hayti, and 2,600 fathoms near the south-east extremity 

 of Portorico. The importance of the division here pointed out 

 will be seen, when we state, that indigenous mammalia of pecu- 

 liar genera are found on the western group of islands only; 

 and it is on these that all the chief peculiarities of Antillian 

 zoology are developed. 



Mammalia. — The mammals of the West Indian Islands are 

 exceedingly few, but very interesting. Almost all the orders 

 most characteristic of South America are absent. There are no 

 monkeys, no carnivora, no edentata. Besides bats, which are 

 abundant, only two orders are represented ; rodents, by peculiar 

 forms of a South American family ; and insectivora (an order 

 entirely wanting in South America) by a genus belonging to a 

 family largely developed in Madagascar and found nowhere else. 

 The early voyagers mention " Coatis " and " Agoutis " as being 



