236 PROCEEDINGS OF THE NATIONAL MUSEUM Vol.89 



measures: Length, 15.4 mm. ; greater diameter, 7.6 mm.; lesser diame- 

 ter, G.5mm. 



The species is easily distinguished from P. (P.) erecta and P. (P.) 

 lurida by its much less strongly developed sculpture. 



PARACHONDRIA (PARACHONDROPS) DAUDINOTI ( [Gundlach] Pfeiffer) 



Plate 21, Figure 9 



1860. Cyclostoma daudinoli [Gundlach] Pfeiffer, Malakozool. Blatter, vol. 6, 



pp. 69-70. 

 1865. Choanopoma daudinoti Pfeiffer, Monographia pneumonopomorum viven- 

 tium, Suppl. 2, p. 105. 



Shell small, elongate-conic, dark horn colored. Nuclear whorls 

 decollated in all our specimens. Postnuclear whorls somewhat 

 inflated, well rounded, marked by narrow, sublamellar axial ribs, of 

 which some are stronger than others, with 2 or even more finer riblets 

 between the strong ones. Some of these riblets become expanded at 

 the summit to form denticles, a few of wliich are rather heavy and 

 hollow. The spiral sculpture consists of mere mdications of threads, 

 wliich, however, render the ribs of the early whorls slightly scalloped 

 and sinuous, that is, articulate. On the last whorl the spiral sculpture 

 is obsolete. Periphery of the last whorl strongly rounded. Here, too, 

 the axial riblets are a little more closely approximated than on the 

 early whorls. Suture strongly constricted. Periphery inflated, 

 strongly rounded. Base short, well rounded, moderately broadly, 

 openly umbilicated, marked by the continuations of the axial riblets 

 and by 2 faint spiral threads outside of the umbilical margin and by 3 

 strong spiral threads within the umbilicus, which here render the axial 

 riblets scalloped. Last whorl solute for about one-fifth of a turn. 

 Aperture very broadly oval, almost subcircular; peristome double, 

 the outer flaringly expanded all around except on the parietal wall, 

 where it is quite narrow, marked by a series of concentric lamellae; 

 the inner slightly exserted and slightly expanded. Operculum 

 typically parachondroid, i. e. upon the chondroid base there is a strong 

 development of retractively curved axial riblets, which are fused on 

 the inside, and wliich become diminished as they approach the 

 periphery, vanishing before reaching the outer extremity. This is the 

 only Cuban species we know in which the operculum agrees with the 

 Jamaican species in the strong development of the opercular charac- 

 ters. 



The specimen figured, U.S.N.M. No. 355387, comes from Monte 

 Toro, Guantinamo. It has 5.1 whorls remaining and measures: 

 Length, 8.9 mm.; greater diameter, 4.3 mm.; lesser diameter, 3.4 mm. 



Gundlach says of the animal: "On rocks. Animal whitish, neck 

 a httle brownish, wliite about the eyes. Blackish dots on the head 

 form a longitudinal line on each side which passes through the base of 



