THE NAUTILUS. 75 



which upset his former ideas. Land shells are very scarce in the 

 state of Maine, at least in the parts I have visited. As a rule two 

 or three specimens of the larger species, would he all one would find 

 after a careful search, not so, however, on the small islands. Pyra- 

 midula alternata occurs in great profusion. Poli/gyrn nlbolabris and 

 Helix horteiisis are also abundant. P. alternuta occurs on one island, 

 some distance from any trees, just above high water mark, its only 

 shelter being rocks and small raspberry bushes. In this location 

 some two hundred, including the albino, were found. On another 

 island it occurs in the woods but crawling on the ground, so numer- 

 ous is it, that one can hardly step without crushing the shells. Fur- 

 thermore it was found feeding on animal matter, dead crabs and 

 shells left by the crows were covered with hungry individuals. 



THE SYSTEMATIC POSITION OF SPHYRADIUM ("PUPA") 

 EDENTULUM Drap. 



BY DR. V. STERK1. 



For some time, it has been my opinion that this species (= Vertigo 

 simplex Gld.) has nut its proper place under Pupa. The shell, 

 though Pupa-like in its general aspect, shows two marked differences 

 from all groups of that genus as well as all Pupidte. In the first 

 place, its aperture is radial, while in the Pupidse it is lateral, or tan- 

 gential, from the columellar wall being prolonged to the periphery 

 of the penultimate whorl, or even beyond it. In the second place, 

 the peristome in Pupidne is more or less everted, generally with a 

 more or less distinct lip, or at least the margin is " finished up," in 

 mature specimens, while in tdeiititlum the peristome is straight and 

 simple, and the margin always thin and sharp, as it is in Patula, 

 etc., and in the Zonitidie. 



This view is now confirmed by the examination of the radula. 

 The teeth are small, comparatively, and the cusps of all are very 

 short and small. There are r+21 (20) in a transverse row, and 

 116-127 such rows were counted. The centrals are tricuspid, the 

 laterals all bicuspid, except the last which is a minute nodule ; in 

 the others there is no difference of laterals and marginals but that 

 the plates of attachment become shorter towards the margins, and 



