CUBAN ANNULARIIDAE TORRE AND BAKTSCH 197 



The type has 46 of these ribs on the first postnuclear whorl and 104 

 on the last turn. These ribs almost alternately, though irregularly, 

 form hollow cusps at the summit. Sometimes a second nodule 

 appears on the ribs below the cusp at the summit. Suture strongly 

 constricted. Periphery inflated, well rounded. Base short, well 

 rounded, openly umbilicated, marked by the continuation of the 

 axial ribs and by 5 spiral threads, within the umbilicus ; these threads 

 grow consecutively stronger toward the outer edge of the umbilicus. 

 Umbilicus open. Last whorl solute for a fraction of a turn, although 

 the outer peristome at the parietal wall usually touches or is adnate 

 to the preceding turn. Apertm-e broadly oval; peristome double, 

 the inner slightly exserted; the outer broadly expanded, more so on 

 the inner lip than on the outer, marked by concentric laminae. The 

 outer peristome is deeply infolded on the middle of the inner lip, 

 hence the name. It forms a slight amicle at the posterior angle of 

 the aperture. Operculum typically opisthosiphonid. Siphon at the 

 posterior angle of the aperture directed into the suture. 



The type, U.S.N.M. No. 493371, comes from the Sierra de Caballos, 

 Isle of Pines. It has 4.4 whorls remaining and measures: Length, 

 14.6 mm.; greater diameter, 8.7 mm.; lesser diameter, 6.3 mm. 



The plication of the inner lip of the outer peristome wull readily 

 distinguish this species from 0. (0.) moreletianum. 



OPISTHOSIPHON (OPISTHOSIPHONA) PLICATUM subspecies? 



On the Isle of Pines, off Punta Colombo, on a small island known as 

 Morrillo del Diablo, Bartsch collected a lot of dead shells, U.S.N.M. 

 No. 391972, which are too poor to serve for description. These 

 appear to be a distinct subspecies of plicatum. The place was so 

 heavily infested with spinose cacti that collecting was next to 

 impossible. 



OPISTHOSIPHON (OPISTHOSIPHONA) TURIGUANOENSE, new species 



Plate 15, Figure 7 



Shell elongate-ovate, pale chestnut-brown, the peristome white 

 with a brownish flush. Nuclear whorls 2, somewhat inflated, well 

 rounded, microscopically granulose, forming a blunt apex. The first 

 postnuclear whorls with rather distantly spaced, sublamellar axial 

 ribs, which on the succeeding turns become reduced and more approxi- 

 mated, and which become rather feebly expressed on the last turn. 

 These ribs become expanded at the summit into broad, white, hollow 

 cusps. Of these ribs, 27 are present on the first whorl and 120 are 

 on the last. Suture moderately constricted, rendered conspicuous 

 by the white cusps of the axial ribs. Periphery slightly inflated, well 

 rounded. Base moderately long, well rounded, and marked by the 



