PACIFIC COAST SPECIES. 147 



The genital system (Terr. Moll., V, Plate XIII, Fig-. A) has the same 

 general arrangement as in Arionta XicTcliniana, excepting that in the 

 present species there is at the end of the vaginal prostate a bulb-like 

 process {!•). In A. TrasJci, also, there is a similar process, but attached 

 to the flagellate extension, at the middle of its length, before reaching, 

 the bifurcation. The extreme length of the genital system is 87"™ 

 The lower part of the oviduct is greatly convoluted. 



Ai'ioiitn. I'liflcineta, Nkwcomb. 



Shell depressed-globose, umbilicated, rather thin, smooth, surface 

 scarcely broken by incremental stria^, Avith occasional re- fig.i28. 

 volving lines, horn color, with a median revolving dark- gmr 

 brown band, margined with white; spire little elevated ; 

 whorls 5 to C, scarcely convex, the last flattened-globose, a. ruficincta. 

 descending at the aperture, convex below; aj^erture banded within, 

 oblique, roundly lunate; peristome white, thickened, its inner margin 

 obtusely rounded, the right portion straight, basal and columellar 

 portions reflected, partially concealing the umbilicus. Greater diameter 

 17, lesser 14"""; height, 9""". 



Helix riifocinciu, Nkwcomb, Proc. Cal. Acad. Nat. Sci.,iii, 117(1.^(54). — W. G. Binney, 



L. & Fr.-W. Sh., i, 174, fig. 30:? (1H(J9). 

 J(lhijariifocinda,TuYOS, Am. Jourii. Conch., ii,3l5, pi. vi, fig. 20 (1866). 

 Arionta rufidncia, W. G. BixxEY, Terr. Moll., v, 371. 



Catalina Island,* California, in the Californian Region. 



There is a form with thick shell, heavy peristome, and closed um- 

 bilicus. Greater diameter, 31""". 



Jaw more like the type common in Mevodon than in Arionta; that is, 

 arc^iate rather than arched, maigins rather i)e(;tinated than scalloped 

 by the ends of the ribs, whicli are about 10 in number. 

 • Lingual membrane (Terr. Moll., V, Plate IX, Fig. N) as usual in the 

 genus, with 35-1-5 teeth and 18 laterals, the nineteenth tooth having 

 the inner cutting i)oint split. Another meuibrane has a side cutting 

 point on all the laterals. 



I have examined two individuals, whose genital systems vary consider- 

 ably. That figured on Plate XIV, Fig. B, .of Terr. Moll., V, has a dart 



*I omit the locality San Diego aud Santa Barbara Island, as Dr. Cooper has showu, 

 them to be incorrect. (Proc. Am. Phil. Soc, xviii, 285.) 



