124 THE NAUTILUS. 



" Inhabits Pennsylvania. The lower tooth of the labrum is some- 

 times obsolete." (Say, Journ. Acad. Nat. Sciences Phila., vol. 2, 

 1821, p. 376.) 



NOTE. This is not the comparatively large and conic multidentate form commonly 

 known in recent years as pentodon ; but a five- or six-toothed form which has 

 hitherto been referred to curvidens. 



" Pupa curvidens. Shell minute, ovate, but much elongated, of a 

 spermaceti-white color ; whorls five, convex, smooth, gradually di- 

 m'inishing to an obtuse apex ; suture deeply impressed, aperture sub- 

 triangular, with the front and outer angles rounded, and the outer lip 

 curved inwards, so as almost to make the aperture heart-shaped ; the- 

 transverse margin is straight, and slightly oblique ; the inner lip is 

 also nearly straight, so that these two form a rightangle at their 

 junction ; lip widely reflected, flattened, white ; throat armed with 

 nine teeth ; the longest, somewhat curved to the left, compressed 

 and pointed, is situated on the middle of the transverse lip, and has 

 a small one seated at its left side ; at the front, nearly opposite the 

 large tooth, almost as large and inclined to the left also, is a quad- 

 rangular, blunt tooth, more slightly curved ; on the left margin are 

 three teeth, of which the upper one is larger, and about the size of 

 the basal tooth, of a blunt quadrangular figure; the other two are 

 minute ; on the outer lip are also three teeth, of which the two upper 

 are very small and pyramidal ; umbilicus open. Length ^ inch, 

 breadth ^ inch. 



" This minute species I first found under a loose stone on the 

 ledges at Phillips Point, Lynn, near the Ocean House. * * * * 

 Four of the teeth are very small, and would scarcely be discerned 

 without being highly magnified, and they seem to be seated farther 

 within the aperture ; the small one on the transverse lip, the basal 

 one, and the upper one on the right lip are liable to be wanting. So 

 far as I can ascertain, it has not been previously described, unless 

 several of the teeth have been overlooked. It is nearest allied to 

 P. pentodon " (Gould, Report on the Invertebrata of Massachusetts, 

 1841, p. 189, f. 120). 



" Pupa cincinnatiensis Judge. * * * peristome simple, heavily 

 thickened near the margin, the callus extending over the parietal 

 wall ; aperture contracted by five prominent denticles, seated on thf 

 callus, one prominent on the parietal wall, two on the columella, the 



