COELOCENTRUM, SUBG. SPARTOCENTRUM. 53 



riblets on the penultimate whorl of the specimen shown in 

 fig. 16. 



Gabb's description, with all the others cited above except 

 the last reference, was composite, as he had two very distinct 

 species mixed in his type lot. As much, if not more, of the 

 description applies to C. minorinum var. gabbi as to the pres- 

 ent spe'cies ; but as the figure given by Gabb himself, by Tryon 

 and those by Binney were all drawn from one specimen 

 (drawn in my fig. 15 of pi. 13), I have considered it best to 

 accept this as the type, as Gabb manifestly selected it as such. 



In my former work on this species I mentioned four frag- 

 mentary specimens in the type lot ; but on further examination 

 I find that two of these belong to one individual, which has 

 now been mended, and is shown in fig. 24 of pi. 17. The lower 

 part of the same shell was drawn in fig. 16 of pi. 13. 



J. G. Cooper, in the American Journal of Conchology, iv, 

 1868, p. 212, footnote, states that "Mr. R. H. Stretch has re- 

 cently brought from near Carson Valley, Nevada, latitude 39 

 degrees, fossils, or rather casts, closely resembling the Holo- 

 spira newcombiana and H. irrcgularis Gabb of Lower Cali- 

 fornia. They occur, he says, in the same formation that con- 

 tains Carinifex," etc. Nothing further is known of these 

 fossils. 



C. MINORINUM (Mabille). 



Shell elevated, subcylindrical, deeply and narrowly rimate, 

 toward the apex elongately attenuated, thin, pale buff, a little 

 shining ; apex obtuse, whitish, striate ; four embryonic whorls 

 ornamented with beautiful granulose spiral stria;, visible only 

 under a lens ; spire high, contracting below the apex ; provided 

 with numerous regularly placed, nearly straight riblets ; inter- 

 stices nearly smooth ; whorls 17, convex, regularly increasing, 

 separated by deep sutures, the last whorl of equal width with 

 the penultimate, a little compressed, angular toward the su- 

 ture, very obtusely carinated on the back, solute, slightly de- 

 scending; aperture a little oblique, angular above, ovate, 

 obscurely channelled at base of the columella; peristome 

 spreading, slightly thickened, continuous ; outer margin regu- 



