<><> THE NAUTILUS. 



sculpture, spiral carinte wholly absent on the last whorl or two, or 

 reduced to two or three low angles ; or when developed, more numer- 

 ous and less prominent than in the type form. Contour about as in 

 acutifllosa. Based upon a series of 94 shells from the headwaters of 

 Fall River, S.-E. Siskiyou Co. There is also a series of the same 

 form in the collection labelled "G. circumlineata Tryon, California." 



The Goniobases of the West Coast are fully as variable as those of 

 the East ; and far too many species have been made. The following 

 synopsis is believed to be in accordance with the facts. 



a. Earlier (or all) whorls longitudinally costate. plicifera. 



a 1 . Earlier (or all) whorls spirally keeled. 



b. Last whorl with many spiral keels. occata. 



b l . Last whorl with few spiral keels. acutifilosa. 



b z . Last whorl rounded, not sculptured. rubiginosa. 



a 2 . Earlier whorls convex, without spiral or longitudinal sculpture. 



bulbosa, nigrina, circumlineata. 



G. plicifera Lea includes the following synonyms or slight local 

 races : silicula Gld., 1847, shastaensis. Lea, 1856, rudens Reeve, 

 I860, bairdiana Lea 18G2. Its range extends from the southern end 

 of Puget Sound, Washington, to Pitt and Feather Rivers, California. 



G. bulbosa Gld., 1847, described from the Columbia River, and 

 before me from the Owyhee River, includes newberryi Lea, 1860, 

 from the upper Des Chutes River, both streams being tributary to 

 the Columbia. 



It is doubtful whether G. nigrina Lea, 1856, should be included 

 in bulbosa, but it seems to me very likely. G. nigrina includes 

 draytonii Lea, 1862, and Melania calif ornica Clessin, Malak. Blatter 

 (n. F.) v, p. 189, pi. 4, f. 9, 9 (1882), as synonyms, and G. circiim- 

 lineata Tryon is probably only a variety, distinguished by larger size 

 and more or less malleated whorls, which show spiral flat faces like 

 some forms of Limncea palustris, or sparse low spiral carinsB. G. 

 nigrina, in its several forms, is distributed over northern California 

 from Sonoma and Napa counties rioith to Humboldt, and east to 

 Lassen and Plumas counties. It is characteristic of the Sacramento, 

 as bulbosa is of the Columbia, drainage. 



The fossil G. tayloriana Gabb has the sculpture of occata and 

 acutifilosa, and is probably an ancestral form of these species. 



Fluminicola seminalis (Hinds). Small creek at Eagle Lake; 

 head of Fall River, Southeastern Siskiyou Co.; S. Fork Pitt R., 

 Modoc Co. 



