198 PUPILLIDAE AND RELATED GROUPS. 



uterus. Walls of free oviduct with longitudinal plicae. 

 Spermatheca ovoid (often more swollen than in figure), im- 

 bedded near base of uterine enlargement ; stalk medium, colu- 

 mellar in position. Vagina long with structure of free ovi- 

 duct. Prostate short with few digitate alveoli. Epiphallus 

 (fig. 2) swollen with thick pebbled wall; penial papilla 

 scarcely developed. Penis slender; epiphallar arm short; 

 appendicular arm almost filled by a large papilla, through 

 which appendix opens; appendix of medium length, basally 

 swollen with heavy, transversely trabeculate walls, apically 

 enlarged into a thin-walled sac containing vacuolate mucus. 

 Penial retractor arising from diaphragm and inserting around 

 base of epiphallus (except for heavy muscular sheath, appen- 

 dicular arm is without retractor, although apex of appendix 

 seems to be loosely bound to diaphragm. Atrium quite short, 

 opening very near base of right inferior tentacle. 



Free retractor system much as in Strolilops but origin of 

 right free muscle and separation of left free from buccal mid- 

 way between columellar origin and root of tail. Left free 

 muscle branch to atrium. Digestive system also similar 

 although salivary ducts about as long as glands. 



P. CL.vppi (Pilsbry). 



The anatomy of animals from near Seattle, Washington, 

 collected Aug. 18, 1929, is very similar to that in P. asteriscus. 



Pyramidulinae. 



The anatomy of the ovoviviparous Pyramidula rupestris 

 (Drap.) has been described by Soos (1917), by Hesse (1918) 

 and by Watson (1920) ; a figure of the genitalia (pi. 29, fig. 

 2) has been copied from the last. The spermatheca is not 

 much longer than the vagina. The penis appears much sim- 

 plified although the small diverticulum may represent a ves- 

 tigial appendicular arm. 



Pleurodiscinae. 



Watson's (1920) figures of the genitalia (pi. 29, figs. 3-5) 

 of Pleurodiscus halmei (P. & M.) have been copied. Its vagina 



