HISPANIOLAN AND BAHAMAN ANNULARIIDAE 227 



0PISTH08IPH0N (OPISTHOSIPHON) BETICUL^ATCS, new species 



Shell of medium size, elongate-ovate, white or pale yellow. Nuclear 

 whorls about 2, well rounded, smooth except for the last portion of 

 the last turn, which shows the beginning of the postnuclear sculpture. 

 Postnuclear whorls inflated, strongly rounded, and marked by slightly 

 retractively curved axial riblets, most of which develop hollow cusps at 

 the summit. The spiral sculpture consists of slender threads, which 

 render the entire surface reticulated. Suture channeled. Periphery in- 

 flated, strongly rounded. Base rather short, inflated, strongly rounded, 

 openly umbilicated, and marked by the continuation of the axial ribs 

 and spiral threads. The umbilical wall is also marked by spiral threads. 

 Aperture broadly oval; peristome double, the outer moderately broadly 

 expanded, almost of the same width all around and adnate or free from 

 the preceding whorl at the parietal wall. There is a slight auricle at the 

 posterior angle, embracing the siphon; inner peristome moderately ex- 

 serted and reflected. Operculum typically opisthosiphonid. 



This species appears confined to some of the southern cays of the 

 Ragged Island chain. 



KEY TO THE SUBSPECIES OF OPISTHOSIPHON (OPISTHOSIPHON) 

 RETICULATUS 



Spiral cords on base 12 reticulatus 



Spiral cords on base 8 pannosus 



OPISTHOSIPHON (OPISTHOSIPHON) BETICULATUS BETICUL,ATUS, 



new subspecies 



Plate 36, Figure 7 



This subspecies I collected on the south side of the Buena Vista Cay 

 of the Ragged Island group. It differs from Opisthosiphon (Opisthosi- 

 phon) reticulatus pannosus in having the sculpture less strongly de- 

 veloped and in having a greater number of spiral threads on the base. 

 In the type there are 43 axial riblets on the first, 65 on the second, 55 

 on the third, and 52 on the last seven-tenths of the last of the remaining 

 whorls. There are 6 spiral threads between summit and suture on the 

 first, 13 on the rest, while the base has 12 and the umbilical wall 8. 



The type (U.S.N.M. No. 536847) has 3.7 whorls remaining and meas- 

 ures: Length, 9.3 mm.; greater diameter, 5.5 mm.; lesser diameter, 

 4.7 mm. 



U.S.N.M. No. 390776 contains 19 topotypes from the same source. 



OPISTHOSIPHON (OPISTHOSIPHON) RETICULrATtJS PANNOSUS, 



new sab species 



Plate 36, Figure 5 



This subspecies I collected on Great Ragged Cay about the salt pans. 

 It differs from Opisthosiphon (Opisthosiphon) reticulatus reticulatus 

 in having stronger sculpture and in having the last whorl less inclined 

 to soluteness ; some specimens are adnate. In the type there are 42 axial 



