108 



PROCEEDINGS OF THE ACADEMY OF 



[1881. 



FlQ. 23. 



P. trivolvis. Original. 

 Fig 24. 



urements of the aperture and of the whorl at the junction of the 

 parietal callus in this and 3 (P. amnion), with similar measure- 

 ments in 1 and 2 (P. trivolvis), wiW give a good idea of the relative 

 obtuseness of their cones or tubes, as well as of the inflation or 

 patulous aspect of the aperture, and of its effect on the physiog- 

 nomy of the shell. A typical P. corneus (Britisli specimens) of 

 1"10 inches greater diameter measures -87 inch lesser diameter, 

 while the longitude of aperture is '42, and longitudinal diameter 

 at junction of parietal callus is -30 inch. 



The following original figures from nature, show the Washoe Lake 

 form as above (fig. 23); while fig. 24, from 

 the same locality, also illustrates the 

 distortion resulting by deviation from or 

 eccentricity in plane of coil. 



The sinistral or dextral inquiry led to 

 the discovery that P. bicarinatus is some- 

 times right and sometimes left ; this is an 

 interesting fact, because said species ex- 

 hibits certain analogies with other peculiar 

 and characteristic forms. 



The i-elations of the dextral Carinifex, 

 whose planorboid character led Dr. Lea^ 

 p.MuotoM. Original (distorted), ^o describe it as a Planorhis^ are appar- 

 ently closer to P. bicarinatus than to any other species. The 

 exceeding variability of Carinifex is seen by the figures here given, 



which, however, do not fully represent 

 the range of variation. (Figs. 25, 26, 27). 

 In the light of our present knowledge 

 it should perhaps be regarded only as a 

 coincidence that the very territory from 

 which P. bicarinatus is with the two 

 exceptions of Hemphill's Antioch, and 

 Portland (Oregon) localities, entirely 

 absent, is the territory inhabited by 

 Carinifex, and in which it has been 

 found, either recent or fossil. When the 

 immense area of this territory is con- 

 sidered, the number of localities in 

 which it has been detected, are few ; still 



Fig. -26. 



From 



Lea's types. 



Klamath and 



Canoe Ureek 



specimens. 



Fig. 27. 



From 



Lea's types. 



Klamath and 



Canoe Creek 



Specimens. 



Carin^/'eaii^ewfierryt, and varieties, these fcW are SO related the One tO the 



Variety from 

 Pitt River, Cal. 



1 Binney's L. and F. W. Shells of N. A., Part II, p..74. 



