THE NAUTILUS. 



surroundings and conditions as the island was raised to its present 

 altitude. 



There is need for much study on the distribution and evolutionary 

 history of the Cuban land shells, and perhaps right here will be found 

 the answers to some Cuban geological problems that fairly call aloud 

 to the traveler. There is evidence, for instance, that Cuba was not 



very long ago divided and separated into several islands a large 



east and a large west one with several smaller islands lying between 

 and projecting high above a shallow sea. Almost beyond question 

 there has been a considerable exchange of species between Florida 

 and that portion of Cuba lying directly south of Florida. This may 

 be accounted for most plausibly by the migrating water fowl which 

 divide their seasons between the great swamps of this portion of Cuba, 

 the Everglades in Florida and the more northern waters of the United 

 States. 



If the editors of the NAUTILUS can afford me space later on I 

 would like to give accounts of some of our personal experiences in 

 the field, particularly about the southern edge of the great Zapata 

 swamp, at Vignales in the Organ Mountains of Pinar del Rio, and 

 finally of our race to catch those two most astonishing shells, Uro- 

 coptis elliotti and U. dautzenbergiana, which live only upon the lofty 

 cliffs of two isolated mountains near Guane. 



NEW MICHIGAN LYMNJEAS. 



BY BRYANT WALKER. 



A careful review of the Lymnseas of Michigan, incident to the 

 preparation of Part II of the Michigan Catalogue, has increased the 

 number of species represented in the state fauna from 18 as recorded 

 in 1894 (Rev. Mich. Moll., p. 11), to 28 at the present time. 



In the material examined, the following forms occurred, which 

 seem worthy of specific or varietal recognition : 



Lymnaea pilsbryana n. sp., PI. I, figs. 2, 811. 



Shell ovate-conic, slightly perforate ; dark brownish-yellow, fre- 

 quently tinged with purple, with a light line just below the suture ; 

 whorls 5, convex, with a deeply impressed suture, the three apical 

 whorls small, forming a short conical apex, penultimate whorl twice 



