238 BULLETIN 192, UNITED STATES NATIONAL MUSEUM 



OPISTHOSIPHON (OPISTHOSIPHON) GOL.DINGI, new species 



Shell small, elongate-conic, flesh-colored, with interrupted spiral bands 

 of brown. Nuclear whorls 2, small, well rounded, smooth except for the 

 last portion of the last turn, which shows the beginning of the post- 

 nuclear sculpture. Postnuclear whorls well rouncfed, narrowly shoul- 

 dered at the summit, and marked by slender, retractively curved, rather 

 closely spaced axial riblets. Most of these riblets develop into slender 

 cusps at the summit, crenulating the suture. The spiral sculpture is ex- 

 tremely feeble in Opisthosiphon (Opisthosiphon) goldingi goldingi and 

 strong in O. (O.) g. masticensis. Suture narrowly channeled. Periphery 

 well rounded. Base short, well rounded, openly umbilicated, and marked 

 by the continuation of the slender riblets and spiral threads. There are 

 additional spiral threads in the umbilicus. Aperture almost circular; 

 peristome double, the outer broadly expanded, only a trifle wider on the 

 inner lip than the outer, forming a conspicuous auricle at the posterior 

 angle, which, however, is rendered irregular by the breathing siphon 

 immediately behind it; inner peristome slender, slightly exserted and 

 slightly reflected. Operculum typically opisthosiphonid. 



I am recognizing two subspecies, which the following key will help 

 to differentiate : 



KEY TO THE SUBSPECIES OF OPISTHOSIPHON (OPISTHOSIPHON) GOLDINGI 



Spiral sculpture strong masticensis 



Spiral sculpture feeble goldingi 



OPISXHOSIPHON (OPISTHOSIPHON) GOLDINGI 3IASTICENSIS, new subspecies 



Plate 37, Figure 12 



This subspecies differs from Opisthosiphon (Opisthosiphon) goldingi 

 goldingi in being larger, with a much greater number and more closely 

 spaced axial ribs and a stronger spiral sculpture. The type has 64 axial 

 riblets on the first, 130 on the second, and 140 on the last of the remain- 

 ing turns. The spiral sculpture consists of strong, well-defined threads, 

 which equal the riblets in strength. The combination of these two sculp- 

 tures forms a clathrate surface. Of these spiral threads, 10 occur on the 

 first and 12 on the remaining whorls. 



The type (U.S.N.M. No. 355524) was collected by C. C. Allen at 

 Mastic Point, northeastern Andros Island. It has a little more than 3 

 whorls and measures: Length, 10.4 mm.; greater diameter, 5.9 mm.; 

 lesser diameter, 4.7 mm. 



U.S.N.M. No. 359887 contains a topotype from the same source; it 

 has a Httle more than 4 whorls and measures : Length, 11.6 mm. ; greater 

 diameter, 6.2 mm. ; lesser diameter, 4.9 mm. 



