302 On Prophysaon, etc. 



and even at the time of writing his article, St, Simon might 

 have learned from the first volume of the "Terrestrial Mol- 

 lusks of the United States" that many Helices have the most 

 simple form of genitalia, while several true Zonites have the 

 dart, dart sac, and some form of multifid vesicle. As to the 

 presence or absence of ribs upon the jaw, or a median pro- 

 jection to its cutting edge, we were well aware from our own 

 observations that those characters were valueless for the pur- 

 poses of distinguishing Zonites from Helix. Our doubts as 

 to the correctness of the reference by St. Simon of Helix 

 lychnuchus to Zonites, were confirmed on finding the allied 

 species* of the subgenus Dentellaria, H. orbiculata, Fer., 

 Isabella, Fer., dentiens, Fer., and perplexa, Fer., to be 

 true Helices. All of those species have the quadrate mar- 

 ginal teeth which characterize the genus Helix, while, as is 

 well known, the genus Zonites is characterized by aculeate 

 marginal teeth. Moreover we did not observe in any of the 

 above species the marginal furrows above the edge of the 

 foot, the distinct locomotive disk, or the caudal mucus pore 

 prevailing in Zonites. 



Confident, therefore, that the species would prove a true 

 Helix, we have for some time endeavored to obtain speci- 

 mens of the animal, but have only recently succeeded in so 

 doing. Through the kindness of Mr. A. Schramm we are in 

 receipt of several specimens preserved in glycerine, from 

 Guadeloupe. On examination of these specimens we find, 

 from both external and internal characters of the animal, 

 that our surmises are corroborated in every particular. The 

 species, therefore, animal as well as shell considered, must 

 remain in Helix, as now accepted by von Martens and most 

 authors. 



Helix lychnuchus. Lingual membrane (pi. xiv, flgs. 7, 8), long and broad. 

 Teeth arranged in numerous horizontal rows. Centrals tricuspid, laterals 

 bicuspid, the side cusps of each being subobsolete ; marginals quadrate, 



* Two more of this subgenus are described below in this paper, p. 305, .306. 



