HELIX. 129 



A species inhabiting the neighborhood of the sea, and very 

 variable in its growth, so as to have given rise to several synonyms. 

 These several forms have been critically discriminated by supposed 

 characters which simply merge together when large series of 

 specimens are compared. To Dr. Dall belongs the merit of having 

 first published this fact. He writes: 



"The shell generally has from five to seven well-marked whorls ; 

 but under especially favorable conditions, as near the walls of Fort 

 Marion, at Saint Augustine, it may have ten or twelve. The number 

 exhibited on the base is absolutely inconstant when specimens from 

 various localities are compared. Only by breaking into the last 

 whorl can it be determined whether the parietal lamina exists. Iii 

 specimens labelled septemvoha by Mr. Binney I have found it and 

 it is often absent in what is otherwise typical cereolus. The soft 

 parts in all are very uniform." 



The synonyms are H. septemvolva, Say, (figs. 27-29), H. volvoxis, 

 Parreyss, (fig. 35), H. microdonta, Desh. (figs. 36-38), H. plaita, 

 Danker, H. Carpenteriana, Bland, (figs. 39, 40), H. Febigeri, Bland, 

 (figs. 41, 42), H. delitescens, Shuttl. H. polygyrata, Pfr. H. cheilodon, 

 "Say," Pfr. H. planorbula, Lam. 



H. PALUDOSA, Pfr. PI. 27, figs. 43-45. 



Umbilicated, brownish corneous, thin, shining, obliquely costulate 

 above, substriate below; whorls 5, periphery subangulated, base 

 more convex; aperture obliquely lunar, peristome reflected, sublabiate 

 within, parietal wall with a small tooth, sometimes absent. 



Diam. 10 mill. 



Ouba. 



It is H. Ungulata, Fer., H. Ramonis, Orb., H. Bardenflehtii, 

 Villa. 



H. LUNDII, Morch (unfigured). Brazil. 



Subsection III, POLYGYRELLA, Bland. 1869. 



H. POLYGYRELLA, Bland and Cooper. PL 27, figs 46-49. 



Widely umbilicated, shining, translucent, yellowish corneous, 

 costulate above, the ribs becoming obsolete at the aperture, base 

 smoothish ; whorls 7-8, somewhat convex, slowly increasing, the last 

 shortly deflected in front, with radiating series of three teeth, remote 



from the aperture and from each other, and visible through the 

 9 



