WEST AMERICAN PYRAMIDELLID MOLLUSKS. 35 



TURBONILLA (CHEMNITZIA?) GABBIANA Cooper. 



Chemnitzia gabbiana Cooper, Am. Joiirn. Conch., vol. 6, 1870, p. 6Q= Turbonilla 

 graciUima Gabb, Proc. Cal. Acad. Sci., 1865, p. 186; not Chemnitzia gracillima 

 Carpenter, Cat. Maz. Shells, 1856, p. 431; + Turbonilla {Chemnitzia f) monterey- 

 ensis Dall and Bartsch, Proc. U. S. Nat. Mus., vol. 33, 1907, pp. 494-5. 



Mr. Gabb's description is as follows: 



Shell small, very slender, long, white; vertex broken; whorls eleven or more, flat- 

 tened on the sides; sutures strongly impressed, ribs about 23, large, obtuse, running 

 from the suture to the margin of the base; base con vexly truncated, smooth; aperture 

 subcircular; columella thick. Length 10 mm., diameter 3.3 mm. 



Habitat, Monterey, California; Dr. J. G. Cooper, collector. This shell can be readily 

 distinguished by its extremely slender form and the strong, slightly oblique ribs. 



The type, according to Mr. Gabb, is in the collection of the Cali- 

 fornia Geological Survey,'^ but appears to have been misplaced or 

 lost. From the description ^\^e are led to believe that it is a form 

 similar to T. torquata, but of considerably broader spire. 



TURBONILLA (CHEMNITZIA) .ffilPYNOTA, new species. 

 Plate 2, figs. 10, 10a. 



Shell small, elongate-conic diaphanous. Nuclear whorls two and 

 one-half, small, helicoid, forming a moderately elevated spire, having 

 their axis at right angles to that of the succeeding turns, in the first 

 of which they are about one-fifth immersed. Post-nuclear whorls 

 high between the sutures, very strongly shouldered at the summits, 

 Somewhat contracted at the periphery, well rounded, marked by 

 strong, sublamellar axial ribs that render the summits strongly 

 crenulate. Sixteen of the axial ribs appear upon the first and 

 second, 18 upon the third, fourth, and fifth, and 20 upon the remain- 

 ing turns. Intercostal spaces a little wider than the ribs, deeply 

 sunk below the general surface, extending to the suture on all the 

 turns of the spire. Sutures strongly marked. Periphery of the last 

 whorl feebly angulated. Base short, well rounded, smooth. Aper- 

 ture rather large, subquadrate, posterior angle obtuse; outer lip thin, 

 bent abruptly anteriorly toward the columella, which it joins almost 

 at right angles; columella very slender and gently curved. 



The type (Cat. no. 162443, U.S.N.M) has eight post-nuclear whorls 

 and measures: Length 3.2 mm., diameter 0.9 mm. It was collected 

 by Mr. F. W. Kelsey, in 30 fathoms, off San Martin Island, Lower 

 California. Three additional specimens (Cat. no. 163242, U.S.N.M.) 

 were collected by Mrs. Oldroyd, at San Pedro, California. 



a Proc. Cal. Acad. Sci., 1865, p. 183. 



