GASTROPODA. 971 



lxipbp:r. holtotcra*.) 



'IICA IIKI.HTKRK8 SoUfT, var. WI8CONSINENSI8, H. I 



i-i \rt j.\\(\ FIGS. 



Mietm* SAI.TKK, I860, Can. Org. Rom., Deo. 1. p. 21, pi. i v, flgs. 2 



ktUeterttet trieannaUt (part. ) WIIITKIILD, 1888, 0ol. of WU., vol. Iv, pp. 219 and 120 



lit 28 to 68 mm.; apical angle of upper volutions 58 to 65, of entire full 

 grown shell 40 to 45'. Volutions five or six, of which the first three or four are 

 closely roiled aii'l the last one or two, or even three, are free and widely separated. 

 The free whorls are marked on the exterior by five keels, the uppermost being the 

 least -li-tm.-t and representing the suture line; the second is stronger and in the 

 upper part of the shell situated almost midway between the suture line and the 

 Peripheral angle, but after the whorls become free it 'is moved relatively much 



>r the sutural edge; the third or peripheral carina is the strongest and most 

 prominent. an>l l.luntly or rounded flat, or even concave at the edge; above it the 

 surface is decidedly concave, beneath it for the greater part to the fourth carina 

 almost flat; the latter is situated about the same distance from the central keel as 

 the second but is scarcely as strong; the fifth keel is relatively weak and situated 

 <>ii the base of the whorl. Surface with distinct, sharp, equidistant lines of growth 

 averaging eight or nine in 5 mm. Their course from the suture to the peripheral 

 angle is almost direct, as it is also from here to the basal keel. Near and on the 

 ITI ipheral keel a more or less abrupt retral curve occurs, indicating an unusually 

 restricted notch in the outer lip of the aperture. 



In casts of the interior the two upper carina' appear as very near each other, 

 yet di-tm-m-hable as far up the spire as the third or even the second volution. 

 The peripheral angle, though gradually losing its prominence, may be recognized 

 on all the whorls. The fourth is but rarely distinguishable, the fifth, never. 



The above describes the main characters of the Wisconsin and Minnesota 

 variety of this species. As may have been noticed, it differs in two respects from 

 the typical Canadian form, namely, (1) the surface stria; are more regular and much 

 less carved back war 1 in coriM'.pience of which the insinuation in the outer lip of 

 the aperture is relatively very small; second, they have a basal or umbilical keel 

 similar to the one in /,. .-.mil-ii-n which is wanting in the typical variety. The 

 latter occurs not only in Canada but in central Kentucky as well, while the var. 

 fonsintnuis is, so far as known, restricted to the northwestern area. 



This fine Lopli though really widely different, greatly resembles, in the 



usual condition in which they occur, the prr -. /. ->i/at>i. Uoth are 



strongly carinated and have the last whorls free, while the surface stria- also are 

 -imilar in being strong and -harp in both. Still, when the -hells themselves, or good 

 molds of their exterior surface, could be compared, we found little difficulty in 



