246 



SCIENCE. 



[N. S. Vol. XVII. No. 424, 



elimination and variation in Pliilosamia 

 cynthia was first considered. 'It was 

 shown that pupal elimination is directly- 

 related to variation, selection being 'secu- 

 lar' (with reference to type) as well as 

 'periodic' (with reference to variability). 

 Samia cecropia exhibits only periodic se- 

 lection. Reproductive selection appears 

 clearly in Samia cecropia. 



The Tortugas as a Biological Station for 

 Eesearch: Alfred G. Mayee, Museum 

 of the Brooklyn Institute of Arts and 

 Sciences. 



The Tortugas occupy what is probably 

 the most favorable situation from which 

 to study the tropical life of the Atlantic 

 Ocean. Extensive coral reefs surround 

 the islands, and in the immediate neighbor- 

 hood one finds reef flats, sandy bottoms, 

 coral mud and a great variety of habitats 

 for a rich and varied fauna. Pure deep 

 ocean water surrounds the group, and 

 their separation from the Florida coast is 

 sufficient to prevent the impure water of 

 the mangrove swamps from contaminating 

 the ocean water of the Tortugas. It is, 

 therefore, possible to maintain larva alive 

 for many weeks in aquaria. The tem- 

 perature of the surface waters in the im- 

 mediate vicinity of the Tortugas is re- 

 markably high, being from 74° to 77° in 

 winter and 80° to 86° in summer. It is, 

 therefore, warmer than any other part of 

 the Atlantic Ocean, excepting the Bight 

 of Biafra, and is almost identical in tem- 

 perature with the waters surrounding the 

 Fiji Islands. The northern edge of the 

 Gulf Stream lies about twenty-five to 

 thirty miles south of the Tortugas, but the 

 prevailing easterly and southerly winds of 

 the spring and summer months drive the 

 surface waters of the Gulf Stream upon 

 the shores of the Tortugas, thus drifting 

 in great numbers of pelagic animals, which 

 cause the surface tows to be richer in this 



region than at any other place known to 

 the writer, and comparable only to the 

 condition observed in the region of the 

 Kuroshiwo, in the neighborhood of the 

 Philippine Islands. 



The pelagic fauna of the Tortugas con- 

 tains representatives from the coast of 

 Africa and from the entire tropical Atlan- 

 tic, and is in general remarkably similar 

 to that of the Fiji Islands, although spe- 

 cific distinctions between related forms of 

 Fiji and Tortugas can usually be deter- 

 mined. This close relationship is probably 

 due to the similarity of the temperature 

 and the conditions of the reefs. 



The fauna of the Tortugas is strictly 

 tropical. Its special advantages over any 

 station on the Florida coast are purity of 

 the water and the richness of the fauna. 

 In these it appears to be superior also to 

 the West Indies, the Bahamas, and very 

 much richer than the Bermudas. The 

 climate is healthful, and although in the 

 summer months the humidity is very great, 

 it is possible to maintain perfect health 

 and energy throughout the hot season. 

 The recent establishment of a naval coal- 

 ing station at the Tortugas has made it 

 easily accessible from Key West. 



The Phasmidce, or Walking-sticks of the 

 United States: A. N. Gaudell, U. S. 

 National Museum. To be published in 

 Proc. V. S. Nat. Mus., Vol. XXVI., 1903. 

 This paper gives, in monographic form, 

 tables for the separation of the Phasmidse 

 into subfamilies, genera and species, only 

 the forms of North America north of 

 Mexico being included. A few prefatory 

 paragraphs are given bearing upon the 

 nature and habits of the species com- 

 posing the family. Four subfamilies are 

 recognized, one, Timeminas, being described 

 as new, based upon a very remarkable for- 

 ficulid-like form from California. Three 

 genera and as many species are described 



