334 PROCEEDINGS OF THE NATIONAL 2IUSEVM. vol.4]. 



In 1866 Doctor Carpenter added Rissoa (=Alvania) acutilirata} 

 which has been generally considered a synonym of Alvania compada 

 Carpenter, but is in reality quite distinct. 



Six years later Doctor Dall described Alvania purpurea,^ and in 

 1886 he added the following new forms from Alaska:^ Alvania 

 castanea Moller, var. alaskana, Alvania castanella, and Alvania 

 aurivillii. 



The following year Professor Keep gave a terse diagnosis •* of 

 Alvania xquisculpta, which was later redescribed as Alvania 

 grippiana Dall. 



For the next 21 years no additions were made. In 1908 Doctor 

 Dall published Rissoa (Alvania) grippiana,^ and last year the present 

 writer described Alvania halceri from Alaskan waters.*' 



A careful examination of the many bottom samples collected on the 

 west coast by the United States Bureau of Fisheries steamer Alba- 

 tross has added a number of new and interesting forms, some of 

 which come from a considerable depth, while the careful and pains- 

 talving collecting by many private collectors has brought to light 

 other new forms from the littoral zone, all of which are here described. 



Only two species are laiown as fossils, and as fossils only, from the 

 west coast of California. These are Alvania pedroana and fossilis, 

 and come from Sand Rock at San Pedro, California. 



KEY TO THE GEXUS M^VANTA. 



Spiral sculpture much stronger than the axial. 



Axial sculpture reduced to incremental lifies or mere raised 

 threads, which are developed best between the spiral keels 

 or cords. 



Spiral sculpture consisting of strohg keels. 



Spiral keels between the sutures, 6 castan'ella, p. 336. 



Spiral keels between the sutures, 3. 



Adult shell more than 4 mm. long aurivillii, p. 336. 



Adult shell less than 2 mm. long hakeri, p. 337, 



Spiral sculpture consisting of well-rounded cords alholirata, p. 338. 



Axial sculpture consisting of broad, subobsolete ribs •. . . lirata, p. 338. 



Spiral sculpture not stronger than the axial. 



Junction of axial ribs and spiral cords not nodulose. 

 Sutures channeled. 



Shell large and robust; adult more than 2.75 mm. 

 long. 



Penultimate whorl with about 22 axial ribs trachisma, p. 330. 



Penultimate whorl with about 34 axial ribs californica, p. 340. 



Shell small and delicate; adult less than 2.25 mm. 

 long. 



Whorls strongly rounded car pent eri, p. 341. 



Whorls almost flattened pedroana, p. 341. 



' Proc. Cala. Acad. Nat. Sci., vol. 3, 1866, p. 217. * Keep's West Coast Shells, 18S7, p. 65. 



2 Amer. Journ. Conch., vol. 7, 1872, p. 116. 6 Nautilus, vol. 21, 1908, p. 136. 



3 Proc. U. S. Nat. Mus., vol. 9, pp. 307-308. 6 idem, vol. 23, 1910, p. 137. 



