376 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.41. 



anteriorly, passing imperceptibly into the vagina. It contains no 

 folds or pouches, nor is there upon it such a shell gland (prostate) as 

 is found in the Endodontidse. The vagina is a wide tube, free of con- 

 volutions, and it opens to the exterior at the base of the right eye- 

 stalk. 



Spermatheca, small and globular with a slender duct almost as 

 long as the oviduct and vagina. It discharges into the vagina near 

 the lower end of the latter. There is no point of demarcation 

 between vagina and oviduct, but for purposes of study and comparison 

 in the Orthurethra it is convenient to call that part of the duct below 

 where the vas deferens leads away, vagina, and that which is above, 

 oviduct. 



The penis is very small in comparison to the size of the other organs. 

 TMs, however, is characteristic of the Pupillidae. It is not attached 

 to the vagma as usual in this family, and therefore there is no atrium; 

 instead it opens to the exterior, on the vaginal lip. The penis is very 

 slender at the point of exit, but enlarges gradually toward the upper 

 end, where it is half the diameter of the vagina. The vas deferens 

 leads from the center of the female organs, the junction of the vagina 

 and oviduct, to the apex of the penis. The retractor muscle is 

 attached to the vas deferens a little way down from tne apex of the 

 penis and also to the floor of the pallial cavity. Above the attachment 

 of the vas deferens there is no continuation of the penis as in Bifidaria 

 and no long flagella-like appendage as in Pupoides. In S. edentulum 

 the condition is nearer what is found in some of the Vertigos as V. 

 ovata. 



The genitalia are most closely related to the Vertigos of any group 

 of the Pupillidae, thus bearing out the resemblance of the shells. 



The j aw, radula, and genital organs of the European ^S'. edentulum 

 have been described and figured by R. Lehman.^ His figures are not 

 very good, but they show that the genitalia of the animal he had were 

 very different from those of the form now under consideration. As 

 he describes and figures these organs there is one long flagellum on the 

 penis and two short thread-like ones. The larger one has a bulb-like 

 enlargement on the outer end. He also says the oviduct is pouched 

 and folded, and his figure shows a distinct demarcation between the 

 oviduct and vagina. If the species he had was S. edentulum and if his 

 dissections are correct, then the American form is specifically if not 

 also generically distinct from the European, and the name, ^S". simplex 

 Gould, will apply to our snail. 



However, until modern methods of dissection are used on the Euro- 

 pean form, it is perhaps best to continue to refer the American snail 

 to S. edentulum. 



I Lehman, Lebenden Schnecken, etc., p. 142, pi. 14, fig. 49. 



