124 ANNALS NEW YORK ACADEMY OF SCIENCES 



Is THE AXTILLEAX FaUXA DISTINCT TROIM THAT OF THE MaIXLAXD ? 



The introductory paragraph to Scharfl's Chapter on the origin of the 

 We?t Indian fanna is as follows : 



''North and South America are to be regarded, according to Professor Suess, 

 as two essentially distinct land-masses, between which is interposed, as a third 

 element, the area of Central America and the Antilles. This geological dis- 

 tinctness of Central America and the Antilles from the two neighboring conti- 

 nents is scarcely recognizable in the fauna of the great isthmus. But the 

 West Indies are comparable to a wedge driven in between U\o faunistically, 

 more or less, independent and distinct masses. Almost everyone who has dealt 

 with the fauna or flora of the West Indian islands has expressed his surprise 

 at this fact. In position, says Dr. Wallace, the Antilles form an unbroken 

 chain uniting Xortli and South America, in a line parallel to the great Central 

 American isthmus. Yet instead of exhibiting an intermixture of the produc- 

 tions of Florida and Tenezuela, they differ widely from both these countries, 

 possessing in some groups a degree of speciality only to be found elsewhere in 

 islands far removed from any continent." 



Several years ago (11'13) I published a brief note on tbe distribution 

 of occidental spiders, getting the data entirely from Petrunkevitch's 

 catalogue. As has been done here, I roughly divided the western hemi- 

 sphere into four parts and found that 59.8 per cent, of the South Ameri- 

 can genera of spiders were not known elsewhere in America, 21.5 per 

 cent, of those in Central America and Mexico were peculiar to that legion 

 raid 3T.5 per cent, of those from United States and Canada were not 

 found farther south. Of the 133 Antillean genera then considered 13.6 

 per cent, were known only from the West Indies. The present paper 

 includes 171 genera without adding any peculiar ones, so that the per- 

 centage is reduced to 10.5. This would also reduce the percentage for 

 some of the other divisions but the figures as they stand are about as 

 reliable as the data on which the revised ones would be based, genus 

 being an indefinite sort of thing, so that we may conclude that the genera 

 of spiders do not confirm the idea of the distinctness of the West Indian 

 fauna. Instead of being very distinct from the mainland they are less 

 so than any of the mainland divisions are from each other. Is this be- 

 cause spiders are more generally distributed than other animals or is the 

 impression of distinctness an erroneous one based on a consideration of 

 special cases ? 



The best way to settle the question of the distinctness of the Antillean 

 fauna is to study carefully a number of groups which are fairly well 

 represented in the Antilles and we are doing this in connection with the 

 survey of Porto Eico which is being carried on under tlie auspices of the 

 Xew York Academv of Sciences. ^lammals were used bv Wallace with 



