mSPANlOLAN AND BAHAMAN ANNULARHDAE 57 



lamellar, axial ribs, which are separated by spaces about twice the 

 width of the ribs. These ribs become slightly intensified at the summit, 

 which they render finely serrulate. The spiral sculpture consists of 

 feeble threads, best developed on the whorls preceding the last ; they are 

 also a little narrower than the spaces that separate them and render 

 the axial riblets almost vertebrated. On the last whorl the spiral sculpture 

 becomes much enfeebled. Suture moderately constricted. Periphery in- 

 flated and well rounded. Base moderately long, very narrowly umbilicated, 

 inflated, well rounded, and marked by the continuation of the axial ribs 

 and spiral threads, the latter increasing in strength toward and in the 

 umbilicus. Aperture ovate. Peristome double, the outer almost evenly 

 broadly expanded all around, forming a slight auricle at the posterior 

 angle ; the inner moderately exserted. Operculum simple. 



The above description is based in part upon Pfeiffer's description 

 and in part upon enlarged photographs of the type, which is in the 

 British Museum. I have not seen specimens of this species. The type 

 here figured has 4 whorls remaining and measures: Length, 17.5 mm. ; 

 greater diameter, 10.5 mm. 



Pfeiffer states that the shell was collected by Salle in "Santo 

 Domingo." 



CHONDBOPOMA (CHONDBOPOMA) SEMILABEIS (Lamarck) 



Plate 11, Figure 5 



1822. Cyclostoma semilahris Lamarck, Histoire naturelle des animaux sans verte 



bres, vol. 6, pt. 2, p. 146. 

 1920. Chondropoma (Chondropoma) semilabre Henderson and Bartsch, Proc. 



U. S. Nat. Mus., vol. 58, p. 62. 



Decollated shell elongate-ovate, pale straw-colored, with interrupted 

 spiral bands of brown; the dashes composing these bands are arranged 

 in both axial and spiral series. The interior of the aperture is a little 

 darker than the outside, showing the color bands within. Peristome 

 white. Nuclear whorls 2, well rounded except for the last portion of the 

 last turn, which shows a few incremental lines. The nuclear spire is 

 blunt at the apex; the remaining turns are strongly rounded, narrowly 

 shouldered at the summit, and marked by slender, low, rounded axial 

 riblets, which are about as broad as the spaces that separate them, and 

 by numerous spiral cords, which are as strong as or a little stronger than 

 the axial ribs and a trifle more distantly spaced than these. The junc- 

 tions of the axial ribs and the spiral cords form low, rounded tubercles, 

 which give to the entire surface of the shell a finely granulose aspect. 

 The spaces inclosed between the axial ribs and spiral threads are almost 

 squarish pits. Suture rendered slightly channeled by the weak shoulder 

 at the summit, which is crenulated. The periphery of the last whorl is 

 well rounded. Base moderately long, well rounded, narrowly umbilicated, 

 and marked by the continuations of the axial ribs and spiral threads, 



