48 THE NAUTILUS. 



from the Park Lakes, and having no connection whatever with them, 

 a new locality for the Lyogyrus, and he assures me that he found 

 them there in great quantities. — H. F. Carpenter. 



PUBLICATIONS RECEIVED. 



The Mud Snail: Nassa obsoleta — By Abigail Camp Dimon. 

 (Cold Spring Harbor Monographs, V, 1905.) This is a very 

 exhaustive treatise on its distribution, structures and functions, 

 breeding and development ; experiments on its relation to external 

 factors, such as light, gravity and currents: resistance to desiccation, 

 and different densities of water; response to mechanical stimuli, 

 food, etc.— C. W. J. 



Notes on some Fresh-water Shells from the Yukon 

 Territory. — By J. F. Whiteaves (The Ottawa Naturalist, xix, p. 

 63, 1905). Five species of Pelecypoda and ten species of Gastero- 

 poda are recorded. 



List of Land and Fresh-water Shells from the District 

 of Keewatin. — By J. F. Whiteaves (Geological Survey of 

 Canada, 1905). About forty species are recorded. 



A Neav Genus and Several New Species of Land Shells 



Collected in Central Mexico by Dr. Edward Palmer 



By William Healey Dali (Smiths. Misc. Coll., Vol. 48, pp. 187-194, 

 plates 43, 44). The new genus Hendersonia :, dedicated to Mr. John 

 B. Henderson, Jr., is a flattened, discoidal, many-whorled snail 

 somewliat like Polygyra cereolus, with the last whorl free and up- 

 turned, Anostoma fashion, and with anatomical characters showing 

 it to be related to Holospira. Nothing of the sort has been known 

 among Cylindrelloid snails hitherto, and the new genus materially 

 enlarges our conceptions of that type of snails. A single species, H. 

 palmeri, is described. Subsequently learning that the name Hender- 

 sonia had been used by Wagner (in Helicinidee, 1905), the new 

 genus was renamed Hendersoniella. Five new species of the genera 

 Xanthonyx, StreptostyJa, Schasicheila and Spheerium are described. 

 The new Xanthonyx potosiana is the greatest of its kind, with a 

 shell 18 mm. in diameter. — H. A. P. 



