CLASS GASTROPODA 
215 
Genus MARGARITOPSIS Thiele, 1906 
Margaritopsis frielei Krause, 1886 
Archiv fur Naturgeschichte, 51: heft 1, 263; PI. 16, figs. 2, a-c. Nachr. Mai Ges. 
15:1906. 
Testa tenuis, alba intus margaritacea, depresso-conica, aspira obtusata, 
anfractibus 4, aequiliter rotundatis, ultimo valde dilatato; axis sutura pro- 
funde impressa; apertura rotundata, labro externo et interno aequiliter 
arcuatis, umbilico lato a basi rotundata omnino non definito. Superficies 
tota striis spiralibus undulatis subtilissimis obducta. (Krause.) Diam. bas., 
10; alt., 6 mm. 
Shell thin, pearly whitish within, depressed-conical, spire obtuse, with 
four whorls equally rotund, the last one strongly dilate, deeply impressed 
at the suture; aperture rotund with six externally equally arcuate, with 
broad umbilicus always undefined at the rounded base. Whole surface 
most finely covered with undulate striae. (Translation.) 
Type in British Museum. Type locality, St. Lorenzbau, one example. 
(Krause.) 
Range. Bering Strait region. 
Genus GIBBULA Risso, 1826 
Shell conoidal, umbilicated; umbilicus cylindrical or infundibuliform; 
whorls frequently tuberculated above and with channeled suture; colu¬ 
mella sometimes terminating in a tubercular tooth. (Tryon, Systematic 
and Structural Conchology .) 
Type. G. magus Linn. 
Distribution. European and Australian seas, Indian Ocean, Red Sea, 
west coast of North America. 
Gibbula adriatica canfieldi Dali, 1871 
Plate 100, fig. 2 
American Journal of Conchology, 7:129. Proceedings of the United States National 
Museum, 24: Pi. 39, fig. 2. 
Shell of seven whorls, the last comprising more than half the shell. 
Above, sutures small but deeply channeled; whorls smooth, with three 
revolving ribs close to the suture, also three or four on the lower part of 
the whorl. Color pearly, with bronze yellow pencillings obliquely to the 
suture. Surface of the whorls rather flattened, semicarinated, convex. 
Shell umbilicated with nine basal revolving ribs. Umbilicus strongly 
[817] 
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