14 THE NAUTILUS. 



cases did not follow this method. However, as the first reviser, his 

 selection may be considered final, or we should practically have to 

 chauge all his names. In the space here available it is not practic- 

 able to give (i full discussion, but the final results may be noted. 



Acmaea cassis Eschscholtz. is a splendid form of A. pelta (Esch.) 

 Cpr., and A. fimbriata Gould, is synonymous. Acmaea pelta Cpr., 

 has five or six synonyms, and as tolerably distinct mutations includes 

 nacelloides Dall ; monticola pars (Nutt.) Cpr.; and olympica Dall 

 (Pilsbry, Man., pi. 8, figs. 92, 93, 94). 



Acmaea patina (Esch.) Cpr., has many synonyms, and, as recog- 

 nizable mutations, ochracea Dall ; emydia Dall (the Arctic testudin- 

 alis of my 1871 paper); cribraria (Gld.) Cpr.; and parallela Dall; 

 the latter corresponding to the A. alveus of the Atlantic coast. 



Acmaea persona Eschscholtz, is not Carpenter's persona (which is 

 a mutation of digitalis Esch.) but is the shell Carpenter called 

 cumingii in 1866 ; though not the same as the prior cumingii of 

 Reeve. A. persona is a fine species, and I have a large series rang- 

 ing from Alaska Peninsula to Socorro Island. 



Acmaea digitalis Eschscholtz, is the northern form which merges 

 into umbonata (Nutt.) Reeve, southward ; and then into textilis 

 Gould, at its southernmost range. Part of Gould's scabra of 1846 

 is the same as textilis Gld. + persona Cpr. (not Esch.) + oregona 

 (Nutt. MS.) Cpr. 



Acmaea scabra Gould, 1846 (from type), is the shell later named 

 spectrum (Nutt. MS.) Reeve, and is generally known under the 

 latter name, which of course must be discarded. 



Acmaea scabra (Nutt. MS.) Reeve, 1855 (not of Gould, 1846), 

 must take the earliest synonym, which seems to be limatula Cpr., 

 1866. 



Acmaea var. funiculata Cpr., merges by imperceptible degrees 

 into the later tenuiscuJpta Cpr., and that into mitra Eschscholtz. 



Acmaea persona Esch. (not Cpr.), merges southward into strigil- 

 lata Cpr. 



Acmaea semirubida Dall, resembles triangularis Cpr., but is more 

 oval in outline, with crimson rays on a white ground ; it ranges from 

 the Gulf of California to Panama. 



Scurria aeruginosa (Midd., 1847, as Patella, with a wrong habitat) 

 is an earlier name for the shell generally known as mesoleuca Menke, 

 1851, from the Gulf of California. 



