132 



PROCEEDINGS OF THE ACADEMY OF 



[March, 



eludes the vas deferens; a rather long and slender epiphallus, and a 

 flagellum. An atrium can scarcely be said to be developed, but the 

 vagina is rather long in all the forms. The globular spermatheca is 

 borne on a long duct, which is lightly bound to the oviduct and is 

 usually somewhat swollen near the middle. The right eye-retractor 

 passes between the d^ and 9 branches, and there is an excessively 

 weak and short penial retractor about I mm. from the end of the 

 flagellum, and inserted on the hmg floor. 



B. a. marice differs strongly from all forms of B. dealbatus by the 

 great length of the penis with its appendages, and of the duct of the 

 spermatheca. Moreover, the penial organs are longer than the 

 spermathecal duct, while in mooreanus and pecosensis the spermathecal 

 duct is the longer. These differences confirm the opinion, derived 



Fig. 5. — A, Bulimulus a. marice. B, B. d. liquabilis. C, B. d. pecosensis. D, 

 penis of a full_v mature individual of same E, B. d. ragsdalei. F, penis of 

 another individual. G, B. d. mooreanus. Fig. D X 2§; the other figures X 2. 



from a study of the shells, that B. alter nat us and dealbatus are well 

 differentiated specifically. 



The measurements of the genitalia in millimeters follows: 



