154 BULIMULUS-PLICOLUMNA. 



ture of oblique growth-wrinkles and numerous spiral series of gran- 

 ules ; H earlier whorls vertically costulate (fig. 82). Whorls 11 % 

 to 12 (13 to 16 according to Cooper) ; the first keeled at the 

 shoulder, concave within the keel, the following increasing whorls 

 convex, becoming less so upon the cylindrical portion of the shell ; 

 last whorl flattened peripherally, and with a spiral sulcus or furrow 

 there (often much less pronounced than in fig. 85). 



Aperture contained about 5J times in length of the shell, irregu- 

 larly oval ; peristome thin, somewhat expanded ; columellar margin 

 narrowly dilated ; columella with a low fold (fig. 83) or none. Ends 

 of peristome connected across parietal wall by a more or less raised 

 and thickened callus. 



Alt. 22 P 5, diam. of cylindrical portion 3'75, alt. of aperture 4 mill. 



"Alt. O'95-l'O, diam. of cylindrical portion 0'18, alt. of aperture 

 0-19 inch." 



Foothills near San Jose de Cabo, Lower California, near edge of 

 lagoons (Bryant & Eisen) ; also on the adjacent mountains (Eisen, 

 Vaslit). 



Rhodea californica subsp. ? ramentosa COOPER, Proc. Cal. Acad. 

 Sci. (2), iii, p. 102 (1891). Columna ramentosa COOPER, t. c., p. 215 

 (1892) ; p. 338, pi. 13, fig. 1 (1893) ; iv, p. 143, pi. 6, f. 19. Plico- 

 lumna ramentosa COOPER, 1. c., v, p. 164 (June, 1895). Bulimulus 

 (Pseudorhodea) ramentosus DALL, Nautilus ix, p. 51 (Sept., 1895) * 

 Proc. U. S. Nat. Mus., xviii, p. 5. Bulimulus (Orthotomium*) ramen- 

 tosus DALL, Proc. U. S. Nat. Mus., xix, p. 363, pi. 31, f. 8 (jaw). 



Sculpture as in B. artemisia, but the shell is more slender, column 

 shaped, like a Cylindrella or Rhodea. 



11 The distinctions between this form and Rhodea have been 

 pointed out in the sectional diagnosis, but it may be as well to call 

 attention to some minor details. The base of the last whorl in B. 

 ramentosus is rounded and the constriction of the peripheral part of 

 the whorl is variable in different specimens. It would almost seem 

 as if the constriction and the gyration of the pillar were in some 

 way correlated, as the pillar above the last two whorls is not gyrate 

 though somewhat tortuous, and consequently the perviousness of 

 the axis does not extend, as supposed by Cooper, to the entire axis, 

 but only to that part of it included in the last whorl and a half or 

 two whorls. The columellar muscle is exceptionally long, and at- 

 tached for several whorls, so that it is very difficult to withdraw the 

 animal from its shell even after it has been long in alcohol. The 



