SUBALPINE MOLLUSCA. 9I 



EXPLANATION OF PLATE. 



1-8 — Sphperium raymondi. la, section profile of figure i. 



9-10 — S. , Klamath Lake, Oregon. 



II — S. lenticula, from near Msalia, Cal. 

 12 — S. partumeium, Worcester, Mass. 

 13, 14— S. partumeium, var.?, Columbus, Ohio. 

 15 — S. partumeium, ] 



16 — S. securis. Section profiles from Prime's dimensions of his 



17 — S. truncatum. | types. 



18 — S. lenticula, J 



19 — Profile of figure 11. 

 20, 21 — S. securis var., Plattsburg, N. Y. 

 22-25— S. truncatum, Massachusetts and Michigan. 

 26— Ancylus caurinus var., Oregon. 

 27 — A. caurinus subalpinus, Yosemite Valley. 

 28 — A. caurinus subalpinus, Bloody Canon, Cal. 

 29 — A. fragilis, near Oakland, Cal. 



30 — Planorbis subcrenatus disjectus, Tuolumne Meadows, Cal. 

 Figure 30 is of natural size; all the others are magnified three diameters, and 

 were drawn from photographs, except the diagrams. In this way some of the 

 specific characters are better developed, without sacrificing the accuracy of the 

 photographic outlines. 



