206 PROCEEDINGS OF THE NATIONAL, MUSEUM Vol.89 



of which there is an infolding, posterior to which the broad flap is 

 reflected over the umbilicus. The outer peristome is marked by 

 concentric lamellae. Operculum typically opisthosiphonid. Siphon 

 at the posterior angle of the aperture directed backward into the 

 suture. 



The specimen figured, U.S.N.M. No. 535474, a topotype, was 

 collected by Drs. Pilsbry and Welch at Loma Cunagua, Camagiiey 

 Province. It has 3.6 whorls remaining and measures: Length, 13.0 

 mm.; greater diameter, 8.0 mm.; lesser diameter, 6.1 mm. 



Bartsch collected a large series on the same limestone block but on 

 the other side. These specunens also show the color variation 

 described for the species. 



OPISTHOSIPHON (CUBIT ASIPHONA) JUDASENSE Torre and Henderson 



Plate 16, Figure 1 



1920. Opisthosiphon (Opisthosiphona) judacensis (Torre and Henderson) Hender- 



son and Bartsch, Proc. U. S. Nat. Mus., vol. 58, p. 68, nomen nudxim. 



1921. Opisthosiphon (Opisthosiphon) judasense Torre and Henderson, Proc. 



U. S. Nat. Mus., vol. 59, pp. 260-261, pi. 41, figs. 9, 10. 



Shell elongate-conic, ranging from pale brown to darker brown, 

 marked by interrupted spiral bands of dark brown. These bands 

 are almost continuous, and the elements composing them are arranged 

 in both axial and spiral series; interior of the aperture varying with 

 the color of the outside, but always paler than the outside; peristome 

 yellowish white, the outer rayed by the brown bands. Nuclear 

 whorls decollated in all our specimens. Postnuclear whorls strongly 

 rounded, marked by retractively slanting, somewhat sinuous axial 

 riblets, wliich are distantly spaced on the early turns and which 

 become more closely approximated as the shell increases in size. 

 In the type 42 of these riblets are present upon the first of the remain- 

 ing turns, 88 upon the second, 148 upon the third, and 186 upon 

 the last. At more or less regular intervals a number of these riblets 

 extend prominently above the rest and become fused to form a 

 hollow cusp. Suture well constricted. Periphery strongly rounded. 

 Base short, inflated, strongly rounded, marked by the continuation 

 of the axial ribs and within the umbilicus by a series of slender, 

 spiral threads. Aperture very broadly oval, almost subcircular; 

 peristome double, the inner slightly exserted and slightly reflected; 

 the outer broadly, flaringly expanded, a little wider on the inner lip 

 than on the outer, deeply notched on the middle of the inner lip, 

 the portion posterior to the notch being reflected over the umbilicus 

 which it completely overshadows; on the parietal wall the peristome 

 is adnate to the preceding turn; it also forms a conspicuous auricle 

 at the posterior angle of the aperture, which is rendered somewhat 



