176 BELOGONA. 



A single European genus, Leucochroa, is herein referred to the 

 Euadenia ; but it is a degenerate group in genitalia and jaw and 

 may prove to belong to the Siphonadenia, in the vicinity of Helicella 

 (Xerophila), which it resembles in the simple-lipped, chalky shell 

 and the peculiar musculature. The American genus Lysinoe is also 

 aberrant, differing from all other Euadenia in having three club- 

 shaped mucus glands inserted on vagina, and in the doubling of the 

 dart sack ; but it differs from all Siphonadenia as well in having 

 the mucus glands inserted one behind the others, instead of at the 

 same level on the vagina. I have considered it a tangent from the 

 Epiphragmophora circle. Oxychona is still imperfectly known. 



The genera of this division may be tabulated as follows : 



a. New World genera. 



1. Dart sack 1, with subapical constriction, apex attached by a 

 thread to vagina; mucus gland 2-lobed ; jaw smooth; tail not 

 serrate. 



b. Middle and inner lateral teeth 1-cuspid, marginals 3-cuspid, 



[CEPOLIB. 

 bb. All teeth with three subequal cusps, POLYMITA. 



2. Dart sacks 2 ; mucus glands 3, on vagina; tail with serrate keel ; 

 jaw ribbed. 



b. Teeth of normal type; shell subglobose, large, deep colored, 



[LYSINOE. 



bb. Teeth with wide middle and minute side cusps; shell troch- 

 oidal, OXYCHONA. 



3. Dart sack 1 ; mucus glands absent, jaw ribbed ; shell discoidal 

 with thin, simple and acute lip, GLYPTOSTOMA. 



4. Dart sack 1 ; mucus gland single, club-shaped, bifid and bulhi- 

 ferous, or 2 with flat glandular extremities adnate on vagina or 

 d. s., EPIPHRAGMOPHORA. 



nn. Old World genera. 



1. Dart sack 1, well-developed. 



I. Mucus gland single, globose, inserted on dart sack, 



[HELICOSTYI.A. 



bb. Mucus gland acinose ; shell bright colored, CHI,ORJ:A. 

 bbb. Mucus gland divided, lobes sacculated, elongated, 



EULOTA. 



2. Dart sack wanting; jaw smooth; shell strong, chalky and white, 



LEUCOCHROA. 



