124 THE NAUTILUS. 



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

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

 1821, p. 37G.) 



Note. — This is not the comparatively large and conic muliidentate 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- 

 minishing 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 righ tangle 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 r 

 breadth * inch. 



40 



" 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 the 

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



