MUSEUM OF COMPARATIVE ZOOLOGY. 157 



Arionta. (p. 353.) 



The species are not well grouped iu the text. The following is more nat- 

 ural: - 



Arionta nrrosa. Arionta Mormonum Traski. 



Townsendiana. Carpenteri. 



exarala. seqitoicola. 



Dialloensls. 



Californiensis (including n-tfculata * 



Nicldiniana, ramentosa, Bridyesi) Dupetithouarsi. 



* * 



intercisa (including redimila). rnjiciucta. 



* Gabbi. 

 Aycrsiana. * 



* Kelletti. 

 tudiculata.' Siearnsiana. 



The geographical distribution of the species is very peculiar. A. Townsend- 

 iana belongs to the Oregon fauna. I doubt its ever having been found in 

 Tnolumne Co., California. A. Mormonum belongs to the Sierra Nevada 

 counties, as does A. tudiculata, which also is found in southern coast coun- 

 ties. All the others are restricted to the coast counties, ranging as stated in 

 the text, the following being island species: A. ruficincta, Gabbi, intercisa, 

 Ayersiana, and Kelletti. A. Stearnsiana and Carpenteri are Lower Californiau 

 species. 



The lingual dentition of all the species is essentially the same, excepting 

 Townsendiana and ruficincta, which have tricuspid centrals and inner lateral-*. 

 The genitalia are the same in arrosa, exarata, Nicldiniana, Californiensis. Ayers- 

 iana, tudiculata, Traski, Carpenteri, sequoicola, Diablocnsis, and Dupetithouarsi. 

 From these the genitalia of Mormonum differ very essentially, being more 

 nearly allied to that of Anlaiafiddis and infumata. A. Townsendiana has sim- 

 ple genitalia, without the accessory organs usually found in Arionta. A. Kel- 

 letti and Stearnsiana have the organs still more complicated with accessories. 

 A. ruficincta and Gabbi are related by their genitalia to the last, but dill'er 

 considerably in wanting the accessory duct of genital bladder. 



I have not examined the genitalia of intercisa. 



Arionta arrosa, GOCLD. (p. 354.) 



J. G. Cooper, in Proc. Cal. Ac. N. S., 1875, p. 16, indicates a variety, IIi- 

 deriana, and another variety, Stiversiana. 



