190 INVERTEBRATA OF MASSACHUSETTS. 



the left also, is a quadrangular, blunt tooth, more slightly 

 curved ; on the left margin are three teeth, of which the up- 

 per one is largest, and about half 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 -j^ inch, breadth 

 jV inch. 



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

 ledges at Phillips's Point, Lynn, near the Ocean House. It was 

 somewhat broken, so as to give an excellent view of the teeth, 

 since then I have met with it not unfrequenily, in damp places, 

 under leaves and boards, in company with P. modesta. 



The shell goes on regularly narrowing both downwards and up- 

 wards from the middle of the lower whorl. 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. 



Pupa simplex. 



Shell minute, cylindrical-ovate, smooth ; whorls Jive ; aperture 

 circular, toothless; umhilicaied. 



Figure 121. 



State Coll., No. 93. Soc. Cab., No. 2398. 



Pupa simplex, Gould ; £ost. Journ. JVat. Hist., iii. 403, pi. 3, f. 21. 



Shell minute, two thirds of the shell cylindrical, surmounted by 

 a rapidly formed, blunt apex, smooth, light chestnut-colored. 

 Whorls five, moderately convex, separated by a distinct suture, 

 quite smooth ; aperture circular, except for a small section 

 from the posterior portion, which is cut off by the encroachment 

 of the preceding whorl ; lip simple and sharp, slightly everted on 

 the left side, and partially hiding a small umbilicus. No trace of 

 a tooth has been detected in any of the specimens examined. 

 Length ^j inch, breadth g'g- inch. 



