190 ORIGIN OF LIFE IN AMERICA 



fauna. This is a point of considerable interest and import- 

 ance, and requires to be more closely studied in a recon- 

 sideration of the true relationship of the members of other 

 groups of invertebrates. 



This relationship is clearly recognisable among the ter- 

 restrial Isopods or wood-lice, which have been described 

 by Miss Richardson. Tylos latreilli, as already quoted, 

 is a typical Mediterranean species, which has been dis- 

 covered in southern Florida, where also another species, 

 Tylos niveus, occurs. Both, of these are now recorded from 

 Bermuda. The European genus Porcellio is represented by 

 two species, one of them (Porcellio parviciornis) new to 

 science. Metoponorthus sexfasciatus, a typically Mediter- 

 ranean species, also found in the Canaries and Azores, occurs 

 in Bermuda, but nowhere else in America. Another species 

 peculiar to Bermuda (Philoscia bermudensis) is closely 

 related to the west European Philoscia couchi. The 

 American affinities are likewise surprisingly interesting. 

 Uropodias seems to be related to the West Indian genera 

 Haplarmadillo and Sphaeroniscus, and this strikingly distinct 

 genus is quite confined to Bermuda with the one species, Uro- 

 podias bermudensis. The truly archaic Actoniscus ellipticus, 

 which is only known from Bermuda and from the coast of the 

 mainland near New Haven and Long Island Sound, is one 

 of the only two members of the family Trichonisoidae. Its 

 distribution is suggestive of a former land connection towards 

 north-eastern North America. The other Actoniscus is con- 

 fined to California. Finally, Leptotrichus granulatus, also 

 peculiar to Bermuda, may be mentioned as the only odcurrenoe 

 of a very ancient Old World genus in America.* 



The only native spider which, according to Dr. Verrill,f was 

 mentioned by the early writers, was the great silk spider 

 (Nephila clavipes). The enormous webs which this spider 

 constructs between trees at a distance of fifty feet from one 

 to another excited their admiration, and suggested to them 

 that the threads might be used in the manufacture of silk 

 tissues. This has actually been done in Brazil, I believe, 



* Eichardson, Harriet, "Isopods of Bermuda." 

 t Verrill, A. E., "Bermuda Islands,": XL, p. 829. 



