230 AMERICAN JOURNAL 



EEVIEW OF THE GONIOBASES OP OREGON AND 

 CALIFORNIA. 



BY GEORGE W, TRYON, JR. 



The most striking facts connected with the geographical 

 distribution of the Melanians of the United States, I have 

 enumerated in a paper published in the Second No. of this 

 Journal. It will be remembered that mention is there made of 

 the very small number of species inhabiting the States west of 

 the Rocky Mountains ; there appears to be about eleven species 

 — less than three per cent, of the total number of American 

 Strepomatidse. When the territory of our Pacific States shall 

 have been more fully explored, doubtless other forms will be 

 added to their Melanian fauna, but still enough is known to 

 sssure us of their comparative paucity in this region. 



The species enumerated in this paper, were all collected 

 either in the Columbia River, of Oregon, or the Sacramento 

 and Klamath Rivers, of California, and their tributaries; there- 

 fore. Southern California has, as yet, yielded no species. 

 Should any be discovered there, they will, in all probability, 

 prove to be undescribed. 



It is a curious fact that most of these shells bear a close 

 analogy with some of the Pacific Island and Indian forms, in 

 their shape and sculpture. 



Thus, our G. rudens, Rve., is very like Mel Boninensis^ Lea, 

 or Mel. unicolor, nob. There is, moreover, a certain similarity 

 of form, ornamentation, and texture, pervading the whole 

 group, which widely separates them from the Eastern Amer- 

 ican species. 



The tendency to plication of the upper whorls, appears to 

 pervade all of these. In nearly every species, even those 

 described as smooth, individuals occur, in which the ribs are 

 developed on the upper whorls. None ot the species are en- 

 tirely without revolving striae; they are sometimes obsolete, 

 but never entirely lost. 



