A NEARLY EXTINCT RAT. 113 



mous guinea-pig ; and is covered with rather long and silky 

 hairs protruding through a thick fur. Its scientific name 

 is Capromys ihoracatus of True, and the species thoracatus 

 is restricted to Swan Island. The genus Capromys to 

 which it belongs is an interesting one ; for it comprises 

 arboreal forms which are only found in the larger West 

 Indian Islands such as Cuba and Jamaica, where it is in 

 imminent danger of becoming extinct. It is just possible, 

 therefore, that Little Swan Island will, in the future, repre- 

 sent the last stronghold of this pecuhar and old time race of 

 rats, for here they are left absolutely unmolested ; and no 

 enemies, human or otherwise, seem likely to disturb them. 



Scientifically, these rats are allied to the coypu {Myopo- 

 tamus) of South America ; an a.nimal attaining to a length 

 of two feet, which fives in burrows near the water, and 

 feeds on aquatic plants. How these rats came to find 

 their way to Swan Island is a fittie point in the problem 

 of the distribution of species which may be worth 

 referring to ; for as we have seen, there is every reason 

 to suppose that Swan Island has never had any 

 connection with the mainland, and is of infinitely later 

 date, geologically speaking, than the islands comprising 

 the Greater Antilles, being of quite recent coral origin. 

 Indeed, as far as its fauna is concerned. Swan Island might 

 be looked upon as an oceanic or pseudo-oceanic island.* 

 If, as seems most likely, this Swan Island race of rats was 

 derived from the race which inhabits Jamaica (C. 

 melanurus) the original progenitors of the Swan Island 

 species must have drifted over a sea space of at least 

 three hundred and twenty miles ; for Swan Island lies 

 exactly that distance in an almost due westerly direction 

 from the nearest poinfc of Jamaica along the course of the 

 Gulf Stream. The genus is not found on the mainland of 

 Honduras, ninety-eight miles to the south, which puts this 

 comparatively short sea-route out of court. 



For the sake of those who may not have given such a 

 subject a thought, we might add that a journey of this 



* There are no snakes on Swan Island. 



H 



