THE NAUTILUS. 15 



the shade of a gooseberry, an elderberry or a rose, there is snail 

 happiness. Perhaps the small gnawers like some snails better 

 for dinner than others, but it has not been proven. For weeks 

 of collecting there may be no broken shells, but the next day, 

 another range or canyon, dead and broken shells will be the 

 rule. Very few broken Oreoheliz were found in the summer of 

 1914, but in 1913 the same species of Oreohelix met with terri- 

 ble slaughter from the gnawers ; some colonies were entirely 

 destroyed. A group of Sonorellas equipped with an offensive 

 odor seem to be well protected. Of the thousands turned up in 

 1913 not more than half a dozen had been broken, and these 

 were probably mistakes made by meat-eaters lacking in the 

 knowledge of conchology. 



AsHMUNELLA TETRODON n. sp. Plate 1, figs. 1, 2. 



The shell is umbilicate, width of umbilicus contained nearly 

 six times in the diameter of the shell; depressed, angular in 

 front, the angle situated above the middle, and nearly or quite 

 disappearing on the last third of the last whorl; spire and base 

 convex; thin, cinnamon or cinnamon-brown above, fading on 

 the base. The surface has a silky luster, and is very weakly 

 marked with growth-lines; on the base some excessively weak 

 spiral lines may be seen under strong magnification. There 

 are 5J convex, closely-coiled whorls, the last descending a little 

 in front, having a deep, narrow constriction or gutter behind the 

 peristome; behind this gutter it is rather swollen and distinctly 

 striate. The umbilicus is cylindric within, and enlarges at the 

 last whorl. The aperture is very oblique; peristome white or 

 pinkish, reflexed throughout, with a recurved edge, the face 

 rounded. Outer margin bears a long, very slightly retracted, 

 flat-topped or slightly notched tooth. Basal margin is armed 

 with two marginal teeth, the outer one slightly larger. These 

 two teeth are somewhat compressed laterally, and are yoked 

 together by a callus on the edge of the broad lip. The spaces 

 between the three teeth are about equal. The transparent 

 parietal callous bears an obliquely radial tooth, set rather far 

 in, and in old examples having the inner end slightly curved 

 towards the basal lip. The outer end often has a low callus 

 outwardly and sometimes one running in. 



