. West American shells; a description in familiar terms of the principal marine, fresh water and land mollusks of the United States found west of the Rocky Mountains, including those of British Columbia and Alaska ... by delicate cross-lines ofcolor. It is found in the south. Tryonmaintains that this species is only a vari-ety of D. inermis, Hds. Drillia torosa, Cpr., the Knobbed Drill, Figure 145, is found rather farther tothe north. It is somewhat less gracefulthan its southern relative, and is smalleralso. The surface is almost black, but eachwhorl is marked by a spiral row of lightercolore
. West American shells; a description in familiar terms of the principal marine, fresh water and land mollusks of the United States found west of the Rocky Mountains, including those of British Columbia and Alaska ... by delicate cross-lines ofcolor. It is found in the south. Tryonmaintains that this species is only a vari-ety of D. inermis, Hds. Drillia torosa, Cpr., the Knobbed Drill, Figure 145, is found rather farther tothe north. It is somewhat less gracefulthan its southern relative, and is smalleralso. The surface is almost black, but eachwhorl is marked by a spiral row of lightercolored 145 The third species, Drillia mocsta, Cpr., theDoleful Drill, resembles the last, but thewhorls have cross-ribs instead of is a southern shell, and is found under stonesbetween tides. Its color is brown orolive, and its length is one inch. Avariety from San Pedro is smooth,with fine color lines. Drillia empyrosia, Dall, the BurntDrill, is shown somewhat enlarged inFigure 14(3. It has yellowish whorls,with a burnt sienna brown tint on thelater ones, though a paler band showswhite patches where it crosses the is not found near the shore, but isdredged from deep water off Fig. 146, X 4j(*) 160 WEST AMERICAN SHELLS Drillia incisa, Cpr., the Incised Drill, is an in-habitant of Puget Sound. Its shell is similar inshape to Figure 144, but is smaller, being but alittle over an inch in length. Its surface is ash-colored, with reddish, revolving lines. The genus Bela includes a large number of smallshells, most of them from the north, and some ofwhich are obtained by dredging. They are decid-edly spindle-shaped, and many of them have thecharacteristic notch in the outer lip near the upperend of the aperture. The name of many specieswill be given in the List, but on account of theirsmall size and rare occurrence they will not befarther described. Figure 147 shows the shell of thepretty little species named Mangiliamerita, Gld., the Ribbed Mangilia
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectmollusks, bookyear190
