MUSEUM OF COMPARATIVE ZOOLOGY. 255 



C. Sigsbeana. It is smaller and more cylindrical also, and the whorls are 

 much less marked off by the sutures. 



Neither for this nor for the preceding species, C. crystallina, are the details 

 of sculpture satisfactorily rendered on the figures. But the difficulty of getting 

 a characteristic drawing of so minute an object from an unscientific artist is 

 very great. 



Cerithiopsis matara n. s. 



Shell pale brown, straight-sided, conical, with sixteen compact whorls. 

 Nucleus, beginning glassy, smooth, and saccular, in the second whorl becomes 

 strongly transversely ribbed and swollen; the next whorl is a little smaller 

 than the second, and takes on the normal characters of the shell; sculpture 

 consisting of two principal nodulated spirals with a smaller undulated thread 

 between them, and a still smaller waved thread in front of and marking the 

 suture ; the transverse sculpture consists of concave waves (20-23) under 

 the spirals, which cross the whorls but are not conspicuous; base smooth 

 or radiately striate, somewhat concave, bounded by a small double keel of 

 two threads which are covered up in the suture; canal strong, short, wide, 

 twisted; aperture squarish, small; sides of the shell flattened, the sutures not 

 conspicuous. Max. Ion. of shell, 9.75; of last whorl, 2.5; max. lat. of shell, 

 2.25 mm. 



Habitat. Barbados, 100 fms. 



This shell was found mixed with C. crystallina, from which it was easily 

 picked out, owing to its straighter sides, brown color, less rounded base, and 

 turban-like nucleus. 



Cerithiopsis Martensii n. s. 



Plate XX. Fig. 3. 



Shell slender, thin, whitish, elongated, truncated, sharply but not strongly 

 sculptured; remaining whorls about thirteen in number; transverse sculpture 

 of well marked lines of growth curved backward, toward the middle of the 

 whorl, most strongly in the later whorls; also of (on the last whorl about 

 twenty-four) ill defined riblets extending across the whorl; spiral sculpture 

 composed of the usual anterior marginal thread, and two others of which the 

 anterior is the strongest; these rather poorly defined threads rise over the 

 transverse sculpture, but are rarely nodulous, though raised at the intersec- 

 tions; suture moderately distinct; base hardly flattened, with well marked 

 striae of growth, but no spiral ridges; canal short; aperture more rounded than 

 in the last species. Lon. of shell, 11.25; of last whorl, 3.0; lat. of last whorl, 

 2.75; of spire at truncation, 1.0 mm. 



Habitat. Station 5, lat. 24° 15' N., lon. 82° 13' W., in 229 fms., bottom 

 temperature 49°.5. Gulf of Mexico, in 1181 fins., mud, a worn specimen, 

 IT. S. Fish Commission. 



