370 TERRESTRIAL AIR-BREATHING MOLLUSKS. 



The epiphragm is thick, white, parchment-like. 



Jaw as usual in the genus ; 8 ribs. 



Lingual uienibrane (PI. IX. Fig. M) has 36—1—36 teeth ; the thirteenth 

 tooth has the side cutting ix)int ; 16 laterals. 



The genital system resembles very nearly that of Nickliniana. Tlie duct of 

 the genital bladder in this species is, however, very much longer, its accessory 

 duct shorter in proportion, the llagellum of the penis sac longer. There is also 

 a peculiar feature in the genitalia of Traski, a globular organ (probably a dart 

 sac) of about equal diameter with the vaginal prostate, attached laterally to 

 the llagellum of the latter, before it becomes bifurcated. The bulbous expan- 

 sions on the two branches of the flagellum are also much larger in Traski. It 

 is figured in PI. XIII. Fig. H. 



Arionta Dupetithouarsi, Deshayes. 



Shell umbilicated, orbicularly convex, smooth or substriate, dark chestnut, 



lio-hter above, with a dark red, white-margined band ; 



Fie 252 o ' / tj 



^^^ " spire obtusely conoid ; whorls 7 to 8, narrow, rather 



convex, the last inflated ; aperture ovate semilunar, 

 white, and banded within ; peristome simple, nar- 

 rowly reflected, its columellar end arched, dilated 

 and arched above, not covering the moderate um- 

 bilicus. Greater diameter 29, lesser 25 mill. ; height, 



A. Dupetithouarsi. 17 mill. 



Helix Ihipetithanarm, Deshayes, Rev. Zool., 1839, 360 ; in Gueein, Mag. 1841, 



Tab. XXX ; in F^r., I. 169, PI. XCVII. Figs. 8 -10. — Pfeiffer, Mon. Hel. 



Viv., I. 338, excl. var. ; III. 229 ; in Chemnitz, ed. 2. I. 328, PI. LVIII. 



Figs. 6-7 (not PI. LVI. Figs. 3 - 5). — Reeve, Con. Icon., 659. — Gould, 



Te!rr. Moll., III. 14. — W. G. Binney, Terr. Moll., IV. 15, PI. LXXVI. Fig. 



9 ; Pac. R. R. Rep., VI. 114 (1857) ; L. & Fr.-W. Sh., I. 174 (1869). 

 Helix Oregoncnsis, Lea, Trans. Am. Philo. Soc, VI. 100 (1839) ; Obs., II. 100, 



PI. XXVIII. Fig. 9; Trosc'hel, Arch. f. Nat, 1839, 11. 221.— DeKay, N. 



Y. Moll., 46. — Pfeiffer, formerly, Mon. Hel. Viv., I. 428. 

 Aglaja Ihipetitho2iarsi, Tryon, Am. Journ. Conch., II. 315 (1866). 



Puget Sound to San Diego, according to the list of the Smithsonian Collec- 

 tion ; but Dr. Cooper says it is only found at Monterey, California. 



Animal light slate-color or dirty white. 



Jaw as usual in the genus ; 4 ribs. 



Lingual dentition (PI. IX. Fig. R) as usual. Teeth 50—1—50. Tlie cen- 

 trals and first laterals have no decided side cusps, and no decided side cutting 

 points, but the latter is represented by a lateral bulging on the large cutting 

 point; the distinct side cusp and cutting point appear on the ninth tooth. 

 There are about 19 laterals, the twentieth tooth having its inner cutting point 

 bifid. The marginals are as usual in the genus. 



