THE NATURAL HISTORY SURVEY, 



175 



Subfamily Zonitinas. 

 GENUS OMPHALINA Rafinesque. 



Omphalina Rafinesque, Enum., etc., p. 3, 1831. 

 Mesomphix (in part) BECK, Index Moll., p. 7, 1838. 



"Shell rather large and solid but thin, umbilicated, smooth 

 below, lacking teeth or folds within; the lip simple and sharp." 



"Foot double grooved above its margin, the grooves meet- 

 ing above the tail in a mucus pore; sole tripartite; dorsal sur- 

 face from head to mantle entirely lacking longitudinal grooves." 



"Genital system lacking dart sac and other accessory 

 gland. In 0. fuliginosa the penis (P.), is a rather short stout 



FIG. 31. 



Genitalia of OMPHALINA FULIGINOSA Griffith. (After Pilsbry, Proc. 

 Phil. Acad. Sci., 184, pi. i, Fig. 5.) P, penis; agl, albumen gland; ovd, 

 oviduct; rp, retractor muscle of penis; sp, spermatheca; spd, duct of 

 same; vag, vagina; vd, vas deferens. 



sac, with the retractor muscle (rp.) inserted at its apex, and 

 attached distally to the floor of the lung. Internally the distal 

 half of the cavity of the penis is densely, finely and rather 

 sharply granulated; the opening of the vas deferens is near the 

 apex of the cavity, and is not provided with a papilla. The 

 lower portion of the vas deferens (vd.) is enormously swollen; 

 and for a short distance from its insertion it is firmly bound to 

 the penis itself." 



"The vagina (vag.) is curiously swollen near the base. The 



