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part of the Gulf of Mexico, specimens often have a weak keel on the shoulder (form or subspecies plagosum Conrad). Busy con coarctatwn Sowerby Turnip Whelk Plate I a Yucatan area, Mexico. Until 1950 this was considered a very rare species, but dredging activities of shrimp trawlers have brought a large number of them to light. Charac- terized by its turnip-like shape, single row of numerous small, dark-brown spines, and by its golden-yellow aperture. 5 inches in length. Family NASSARIIDAE Genus Nassarms Dumeril 1806 Subgenus Nassarms s. str. Nassarms vibex Say Common Eastern Nassa Plate 2 3q Cape Cod to Florida, the Gulf States and the AVest Indies. % inch in length, heavy, with a well-developed parietal shield. Last whorl with about a dozen, poorly developed, axial ribs which are coarsely beaded. Color gray-brown to whitish with a few splotches or broken bands of subdued, darker brown. A common sand or mud-flat species. Some specimens have numerous weak spiral cords. Parietal shield sometimes yellow- ish. Nassarms acjitus Say Sharp-knobbed Nassa Figure 53c West coast of Florida to Texas. Ya: inch in length, characterized by its glossy shell, its strong, pointed beads, and in occasionally having a narrow, brown, spiral thread connecting the beads. Moderately common. Fossil specimens are twice as large. Nassarms insculptus Carpenter Smooth Western Nassa Figure 53f Point Arena, California, to Lower California. % inch in length, outer lip thickened, parietal wall thick, white but not very wide. Body whorl smoothish, except for weak, fine spiral threads. Axial ribs numerous only on early whorls. Color white, covered by a yellow- ish white periostracum. Moderately common; dredged from 20 to 200 fathoms.