216 PROCEEDINGS OF THE NATIONAL MUSEUM Vol. S9 



OPISTHOSIPHON (CYLINDROSIPHONA) BACILLUM BACILLUM, new subspecies 



Plate 19, Figure 4 



We have seen this, race from El Cacaotal, Sierra de Najaza; Guai- 

 canamar; Vereda del Telegrafo; 9 miles east of Cantera de Montejo; 

 Finca de River6n, Marti; Sierra de Sibanicu and El Zanjon, Sibanicu; 

 all these localities in Camagiiey Province. This subspecies differs 

 from 0. (C.) bacillum. garciai, from Oriente Province in having the 

 sculpture less strongly developed, the nodules of the ribs feebler, 

 and the color bands more pronounced. The type has 29 axial ribs on 

 the first of the remaining turns and 32 on the last whorl. 



The type, U.S.N.M. No. 535423, comes from El Cacaotal. It has 

 4.0 whorls remaining and measures: Length, 7.8 mm.; greater diam- 

 eter, 3.3 mm.; lesser diameter, 3.0 mm. 



DALLSIPHONA, new genus 



The shells of this monotypic genus have a tm-binate shape. They 

 are openly, widely umbilicated, with the surface marked by numerous, 

 fine, closely spaced axial ribs, which are not thickened or gathered 

 into tufts at the summit. The spiral sculpture is confined to the 

 umbilicus. The operculum is typically opisthosiphonid. The siphon 

 is incomplete, i. e., it is connected with the edge of the peristome by a 

 sHt. 



The genus is known only from the southeastern Cubitas Mountains. 



Type: Dallsiphona dalli (Torre and Henderson). 



DALLSIPHONA DALLI (Torre nnd Henderson) 



Plate 19, Figure 6 



1920. Opisthosiphon dalli Torre and Henderson, A new Opisihosiphon from 

 Cuba, privately printed, June 25. 



1920. Opisthosiphon (Opisthosiphona) dalli Henderson and Bartsch, Proc. 



U. S. Nat. Mus., vol. 58, p. 68. 



1921. Opisthosiphon (Opisthosiphona) dalli Torre and Henderson, Proc. U. S. 



Nat. Mus., vol. 59, pp. 254-255, pi. 40, figs. 2, 8, 9. 



Shell turbinate, ranging in color from ivory white or pale brown to 

 pale orange; aperture ivory white. Nuclear whorls 2.7, forming a 

 narrow tip, well rounded, smooth except the last portion of the last 

 turn, which shows the beginning of the postnuclear sculpture. Post- 

 nuclear whorls strongly inflated, very strongly rounded, marked- by 

 slender, closely spaced, retractively slanting axial threads, of which 

 102 occur upon the first of the rem.aining turns in the type, 192 upon 

 the second, and 404 upon the last whorl. These threads are separated 

 by mere impressed lines. Suture well constricted. Periphery 

 inflated, strongly rounded. Base short, inflated, strongly rounded, 

 openly umbilicated, marked by the continuation of the axial riblets 



