12 liemarhs on Classifications of 



in Mesomphix, a subgenus of Hjalina, in the description 

 of tlie animal of which no reference is made to the mucous 

 pore. 



I should mention that Dr. Binney {Terr. Moll. 11. 253), in his 

 description of the animal of H. sivpjpressa Say, adds : " On the 

 upper surface of the extremity of the foot is a longitudinal 

 lissure or furrow, from which mucus exudes in great quantities, 

 and which the animal shuts and closes at will." I have very 

 lately examined the animal referred to, and find the above state- 

 ment correct. Dr. Binney does not allude to that character in 

 his notice on the animal of the very closely allied JI. gularis 

 Say, which I have not at present seen. Looking at the shells 

 alone of supp7'essa and gidaris, they seem to belong to the same 

 genus, but the absence of the mucous pore in the animal of the 

 latter will widely separate these species. 



Differences appear to exist in the form and structure of the 

 mucous pore or slit (subcaudal gland), requiring careful exa- 

 mination. 



Albers, referring to the fulcrum, first mentioned by Lea, has 

 in his description of the genus Stenotrema the following : — " Li 

 quarta parte circuitus anfractus ultimi ante aperturam, colu- 

 mella appendice callosa, lamelliformi, cavationem anfractus 

 coarctante, munita est." 



In my " Bemar'ks on certain species of North American Ileli- 

 cidoB^^ (Annals YI. and YIL), and also in my ^' JVotes on the 

 toothed Helices of North America)^ [Annals, YIL 442), I made 

 various observations on the fulcrum and its modifications, but 

 some further explanation on the subject is necessary. 



The following species have the same form of that accessory 

 process as prevails in spinosa, tlie type of Stenotrema, viz. : 



H. monodon M. & R. H. hirsuta Say. 



barbigera Redf. labrosa Bid. 



Edvardsi Bid. maxillata Gould. 



Edgariana Lea. leporina Gould, 



stenotrema Fer. pustuloides Bid. 



