ARIONTA. 357 



sac there is a decided enlargement, perhaps of the nature of a prepuce, or pros- 

 tate. The vas deferens enters the penis sac below its apex. The retractor 

 muscle is at the apex of the penis sac. There seems no accessory organ, the 

 genitalia being reduced to their simplest type, and thus widely differing from 

 the allied species. 



Arionta tudiculata, Binney. 

 Vol. III. PI. XVI. 

 Shell subumbilicated, orbiculate-convex ; epidermis olivaceous ; spire a de- 

 pressed cone ; whorls between 5 and 6, slightly convex ; body-whorl volumi- 

 nous, expanding somewhat towards the aperture ; aperture transverse, rather 

 circular; peristome whitish, thin, expanded, slightly reflected at the basal por- 

 tion, at the columella dilated, reflected, and almost closing the umbilicus ; base 

 convex ; a well-defined, rather wide, dark chestnut band, margined with a light 

 color above and below, revolves near the centre of the body-whorl, and is more 

 or less visible above the suture on the two whorls preceding the last; surface 

 of the outer whorl covered with somewhat regular impressions or indentations 

 with ridges between, causing it to look as if covered with scales ; when these 

 are not apparent, it is marked with oblique wrinkles. Greater diameter 33, 

 lesser 26 mill. ; height, 19 mill. 



Helix tudiculata, Binney, Bost. Joum. Nat. Hist., IV. 360, PI. XX. (1843) ; 



Terr. Moll., II. 118, PL XVI. — Pfeiffer, Mon. Hel. Viv., I. 283 ; IV. 270. 



— W. G. Binney, Terr. Moll., IV. 7 ; L. & Fr.-W. Sh., I. 165 (1869). 

 Aglaja tudiculata, Tryon, Amer. Journ. Conch., II. 313 (1867). 



A species of the California Region, traced from Washington Territory to 

 San Diego, and even to Todos Santos Bay in Lower 

 California. _" 



I have lately received this species under the name of 

 " H. cypreophila, Newc, Copperopolis, Cal.," from Dr. 

 Newcomb, one of whose specimens is here figured. 



Jaw thick, long, narrow, slightly arched ; ends but 

 slightly attenuated, blunt; anterior and posterior sur- 

 face equally showing 6 stout, broad ribs, denticulating H. cypreophila. 

 either margin. 



The lingual membrane (PL IX. Fig. E), has 50—1—50 teeth, with 26 per- 

 fect laterals ; all of the type usual in the genus. The dentition and geni- 

 talia of cypreophila is similar to those of the typical form. 



Genitalia as in A. Nickliniana. 



Arionta Nickliniana, Lea. 

 Vol. IH. PL VI. a. 

 Shell subumbilicated, conic-globose, rather thin, the surface lightly marked 

 by the lines of growth, faintly indented and delicately shagreened with fine 



