ARIONTA. 363 



ing duct (13c) branches out, but instead of ending in a globular organ, it be- 

 comes much enlarged in size, and ends in enveloping the prepuce (p p). The 

 dart sac contained a small dart of the form figured by Leidy (Terr. Moll. U. S., 

 I.) for Tebennophorus Caroliniensis. The oviduct was closely and spirally 

 wound around the duct of the genital bladder. The testicle and ovary are 

 yellow. 



The jaw is thick, arched, ends blunt, but little attenuated ; anterior surface 

 with 6 stout, separated ribs denticulating either margin, and several less devel- 

 oped, interstitial ribs. 



The lingual membrane is long and narrow with about 50 — 1 — 50 teeth. The 

 centrals are of the form usual to the genus. The cusp with its cutting point is 

 very short, reaching only about half-way to the lower edge of the base of at- 

 tachment. Laterals of same type ; the second has a side cutting point. Mar- 

 ginals low, wide, very variable in the denticles, but usually with one long, 

 broad, sharply bifid inner denticle (the inner point much the smaller), and one 

 short, sharp, rarely bifid outer denticle. There are 24 laterals. The twenty- 

 second tooth has the side cutting point ; on another membrane, the twentieth 

 (PI. IX. Fig. L). 



Arionta exarata, Pfeiffkr. 



Shell umbilicated, depressed-conic, rather solid, malleated and wrinkled, yel- 

 lowish, with one chestnut band ; spire rather acute, conic : 

 whorls 7, equally convex, gradually increasing, the last 

 broader, rounded, scarcely falling in front, narrowed 

 around the open, moderate umbilicus; aperture oblique, 

 broadly lunate ; peristome with a light white thickening, 

 the terminations scarcely converging, the right slightly 

 expanded, the columellar triangularly dilated above and 

 widening. Greater diameter 30, lesser 25 mill. ; height, 16 mill. 



Helix, exarata, Pfeiffer, Proc. Zool. Soc., 1857, 108 ; Mon. Hel. Viv., IV. 268. 



— W. G. Binney, TeiT. Moll., IV. 12 ; L. & Fr.-W. Sh., I. 168, Fig. 292 



(1869). 

 Aglaja exarata, Tryon, Am. Journ. Conch., II. 312 (1867). 



Californian Region, from near San Francisco to Santa Cruz or Marin 

 County, only a range of eighty miles. 



The largest individual I have seen has a greater diameter of 40 mill. There 

 is an albino form. 



Jaw as usual ; 6 riba. 



The lingual membrane (PI. IX. Fig. O) has 54 — 1 — 54 teeth, 19 perfect 

 laterals ; the twenty-first tooth has its inner cutting point split ; the nineteenth 

 tooth is the first with side cusp and cutting point. 



Genitalia as in Nickliniana. 



