176 PROCEEDINGS OF THE NATIONAL MUSEUM Vol.89 



OPISTHOSIPHON (BEKMUDEZSIPHONA) BANAOENSE BANAOENSE Torre and Henderson 



Plate 12, Figure 5 



1921. Opisthosiphon (Opisthosiphona) obturatum banaoense Torre and Hender- 

 son, Proc. U. S. Nat. Mus., vol. 59, p. 253. 



This subspecies was described from Banao off the southwestern 

 part of the Cubitas Mountains, is shorter than 0. (B.) banaoense 

 trincherasense, and usually has the umbilicus more deeply plugged 

 by the reflected inner lip of the outer peristome. The first remaining 

 whorl in the type bears 72 riblets; 152 are present upon the last one. 



The type, U.S.N. M. No. 314950, has a little over 3 whorls remaining 

 and measures: Length, 11.0 mm.; greater diameter, 8.7 mm.; lesser 

 diameter, 6.4 mm. 



OPISTHOSIPHON (BEKMUDEZSIPHONA) BANAOENSE TRINCHERASENSE, new subspecies 



Plate 12, Figure 9 



1920. Opisthosiphon (Opisthosiphona) trincheracensis (Torre and Henderson MS.) 

 Henderson and Bartsch, Proc. U. S. Nat. Mus., vol. 58, p. 67, nomen 



nudum. 



This race was collected by Torre in the Paso de las Trincheras, 

 western end of the Cubitas Mountain. It is more elongate than the 

 typical race and it is usually of darker color. 



The type, U.S.N. M. No. 355473, has 3 whorls remaining and meas- 

 ures: Length, 14.0 mm.; greater diameter, 9.9 mm.; lesser diameter, 

 7.3 mm. It has 56 axial riblets on the first of the remaining turns 

 and 142 upon the last whorl. 



OPISTHOSIPHON (BEKMUDEZSIPHONA) OBTURATUM Torre and Henderson 



Shell ovate, varying from flesh color to horn color, buff to orange 

 or even to brown. Nuclear whorls 2, inflated, strongly rounded, 

 microscopically granulose. Postnuclear whorls well rounded, and 

 marked by retractively slanting, sublamellar axial ribs, the early ribs 

 bearing slender elongated thickenings resembling nodules that would 

 indicate spiral sculpture, which, however, is not present in the inter- 

 costal spaces. The slight spiral sculptured effect, therefore, is a 

 false one. These ribs at irregular intervals become strongly developed 

 at the summit, where they form hollow cusps, which extend up on 

 the preceding turn and which are adnate to it. The spaces separating 

 the axial ribs are much wider than the ribs. Suture well constricted. 

 Periphery well rounded. Base moderately long, marked by the 

 continuation of the axial ribs and several inconspicuous spiral threads 

 on the exposed portion of the umbilical wall. Aperture broadly oval; 

 peristome double, the inner slightly exserted and reflected, par- 

 ticularly so on the outer lip; the outer peristome is broadly ex- 



