MOLLUSCA OF MICHIGAN— WALKER. 459 



CATALOGUE. 



Order PULMONTA. \ 



Sub-order STYLOMMATOPHORA. \ 



i 

 MONOTREMATA. i 



VASOPULMONATA. , 



1. SIQMURETHRA. 



Superfamily HOLOPODA. i 



Family HELICID/E. | 



Foot edges without pedal grooves; sole undivided; marginal teeth with 

 wide, short, squarish basal-plates and one or several cusps, the outer cusp 

 never elevated on middle cusp. Shell usually with an expanded or 

 reflexed lip. 



Sub-family POLYQYRIN/E Pilsbry. 



Genitalia simple; vas deferens inserted directly on the well developed 



long penis, which has no epiphallus or flagellum; no dart sack or mucus \ 



glands; no diverticulum on spermatheca duct; eggs small and numerous. j 



Jaw solid, ribbed or smooth; marginal teeth Avith more than one cusp. : 



Shell with lip thickened within, expanded or reflexed; the embryonic whorls ; 



not distinctly differentiated. I 



43 i 



