154 MICROCERAMUS. 



II. Axis encircled by a thin, wide, median lamella. 



SPIROCERAMUS, sp. no. 20. 



Group of M. gossei. 



A group of very closely related species, one of which, M. 

 gossei, with the forms immediately related to it (concisus, 

 arctispirus, mexicanus, texanus, floridanus and providentia) , 

 has attained a general distribution in the Antilles and on the 

 mainland. The other species stand more distinctly differen- 

 tiated, and are quite restricted in distribution. 



Species of the islands off Venezuela: M. ? Curacao 



(p. 146) ; Pineria (?) bonairensis, Buen Ayre (p. 112). 



Species of the mainland, Central America to Texas: M. 

 kieneri, M. concisus, M. mexicanus, M. texanus. 



Floridian species : M. pontificus, M. floridanus. 



Bahaman species: M. swifti, M. gossei~ providentia. 



Cuban species : M . gossei, M. denticulatus. 



Haitian and Jamaican species: M. gossei. 



1. M. KIENERI (Pfeiffer). PI. 26, figs. 21, 22, 23. 



" Shell shortly rimate, cylindric-turrite, thin, obliquely 

 closely ribbed; irregularly marbled with brown-corneous and 

 whitish. Spire turrite, the apex rather acute, blackish. 

 Suture deep, crenate. Whorls 13, convex, the last about one- 

 fourth the length, obsoletely carinate at the base. Aperture 

 lunate-circular; peristome simple, expanded throughout, the 

 margins converging, right margin deeply arcuate, columellar 

 margin dilated. Length 18, diam. of antepenult, whorl 6 

 mm.; aperture 4.5 mm. long, 4.3 wide." (Pfr.) 



Honduras (Dyson). 



Bulimus kieneri PFR., P. Z. S., 1846, p. 40 (July, 1846) ; 

 Monogr., ii, p. 79 ; iii, p. 365 ; Conchyl. Cab., p. 131, pi. 42, 

 f. 23, 24. Macroceramus k. PFR., Monogr., iv, 689; vi, 350 

 (exclusive of synonym C. pontifica) . BLAND, Ann. of the 

 New York Acad. Sci., 1882, ii, p. 127, fig. in text. 



Known by the original lot only. I copy Bland 's figures of 

 a cotype, f. 21, 22, and Pfeiffer's original figure, f. 23. It is 

 much larger than any other species found on the mainland. 



