384 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 85 



CHONDROPOMA (CHONDROPOMARTES) PRESASIANUM (Gundlach) Pfeiffer 



Shell elongate-conic, flesh-color, with brownish markings that form 

 axial and interrupted spiral elements. These bands of brown show 

 up best on the expanded portion of the outer peristome, where they 

 form alternate areas with the ground color. Postnuclear whorls well 

 rounded, narrowlj^ shouldered at the summit, marked by sublamellar, 

 somewhat wavy, retractively slanting axial ribs and spiral cords ; the 

 junctions of the two form hollow tubercular spines, which, when the 

 tip is broken away, prove to be made up of a mere thin shell of sub- 

 stance. The spaces enclosed between the spiral cords and the axial 

 ribs are rectangular areas having their long axis parallel with the ax- 

 ial sculpture. Suture well constricted. Periphery inflated, strongly 

 rounded. Base inflated, strongly rounded, openly umbilicated, and 

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

 which equal those on the spire. The umbilical wall is also similarly 

 marked, but here the sculpture becomes somewhat reduced. Aper- 

 ture oval, with a slight contraction at the posterior angle ; peristome 

 double, the inner forming a ring, which is slightly expanded, slightly 

 reflected, smooth, and somewhat thickened, the outer forming a very 

 broad, flaring, slightly up-curved expansion, which extends all 

 around in equal width except where it touches the preceding turn at 

 the parietal wall, where it is very narrow. This flaring portion is 

 marked by a series of wavy scalloped lamellae, which form a regular 

 series of elevations and depressions from the inner peristome out- 

 ward to the outer margin. These lamellae are very delicate and in 

 many of the specimens examined have been lost, probably in the 

 cleaning process. On the outside of this expanded portion the ridges 

 forming the fimbriations prove to be extensions of the spiral cords, 

 the areas between them being broader. Operculum thin, horny, 

 paucispiral, with subcentral nucleus, the outside of all but the central 

 whorls being covered with minute calcareous granules. 



Bartsch's field notes, Station 20, Finca El Pan, July 21, 1928, state : 



"Animal short, forehead marked with numerous short brownish 

 streaks. This darkish area is bordered on each side by a flesh-colored 

 zone, which is slightly tinged with smoke gray. This same color ex- 

 tends from this area over the tentacles, which are flesh-color, almost 

 white, with a grayish tinge. The tentacles swell out slightly toward 

 the tip and here are a little darker in color. Sides of the body smoke 

 gray. Sole of foot a little paler than the sides, deeply medially cleft. 

 Motion of the two sides alternate." 



The animals, after being removed from the stones to which we 

 found them cemented, would withdraw deeply within their shells 

 and refuse to come out. Only one did so after a very long wait. In 



