192 PROCEEDINGS OF THE ACADEMY OF [1889. 



b Meal perforation, rounded or rounded-lunar aperture, the lip fragile, 

 simple, columellar margin expanded ; surface nearly smooth or 

 delicately, very obliquely ribbed. The color is brownish or greenish. 

 The species have heretofore been scattered thiough two families aud 

 many subgenera (Acanthinula, Conulus, Pyramidula, etc.) by Pfeiffer 

 and other authors. The species are as follows : H. dioscoricola 

 C. B. Ad., H. punctum Morelet, H. ececa Guppy, JET. plagioptycha 

 Shutt., H. cwcoides Tate, H. ierensis Guppy, H. granum Strebel et 

 Pfeffer. This number will require some reduction, as the first three 

 forms are very closely allied, and the last four equally so. 



MICROPHYSA Albers. 



The note in Proc. Acad. Nat. Sci. Phila. 1889, p. 82, contains the 

 writer's views on this little group, which is allied to Microeonus and 

 the smaller forms of Patula. The name Mierophysa is preoccupied, 

 and may have to be replaced, in which event Thysanophora Strebel 

 may be used, as it seems to be practically synonymous. The section 

 is essentially West Indian. 



PUNCTUM Morse. 



This genus was perfectly defined by Morse, and should, I am con- 

 vinced, be restricted to species agreeing with the original diagnosis 

 in characters of animal. I am unable to follow Mr. Binney in 

 uniting it to Mierophysa, or Dr. Fischer in including Glyptostoma 

 with it. 



HELIX Linn. 



The genus Helix, restricted, after the elimination of those groups 

 possessing distinct structural characters, is capable of division into a 

 moderate number (about twenty) of groups which may be ranked as 

 subgenera. Most of these consisting of a number of minor groups, 

 the characters of which usually merge more or less completely into 

 one another in some species. For the primary divisions of the genus, 

 the characters of the shell, genitalia and dentition have about equal 

 value ; and the consideration of either one of these characters to the 

 exclusion of the others is almost certain to result in a false grouping.* 

 The older writers on land shells, especially Ferussac, defined a large 

 number of subgenera founded on characters of the shell alone ; but 

 most of these groups have proved to be so heterogeneous that we are 



* Semper's classification founded principally on the genitalia is a notable ex- 

 ample of this. The characters of the jaw are of comparatively slight value in the 

 Helices. 



