132 PROCEEDINGS OF THE ACADEMY OF [March, 
cludes 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 & and 2 branches, and there is an excessively 
weak and short penial retractor about 1 mm. from the end of the 
flagellum, and inserted on the lung floor. 
B. a. marie 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. marie. B, B. d. liquabilis. C, B. d. pecosensis. D, 
penis of a fully mature individual of same E, B. d. ragsdalei. F, penis of 
another individual. G, B.d.mooreanus. Fig. D < 22; the other figures x 2. 
from a study of the shells, that B. alternatus and dealbatus are well 
differentiated specifically. 
The measurements of the genitalia in millimeters follows: 
