MAKINE MOLLUSKS — MACGINITIE 105 



the bands. The secondary grooves between the striae of the bands 

 are usually more prominent in var. morchianum. The basal whorl 

 has 2 carinae, one of which is in the same position as that in B. glaciale; 

 sometimes it is angled at this carina and sometimes not. The other 

 carina, more apical in position, is usually stronger and extends around 

 the body whorl and one or two more whorls, often forming a sloping 

 shoulder. Where the carina crosses the axial folds, the latter are 

 drawn out into nodules and the folds usually change direction at this 

 point. Young specimens are covered by a thin, closely adherent, 

 slightly fringed periostracum that is usually worn off in larger speci- 

 mens. Some young specimens are diflScult to distinguish from B. 

 cUiatum, both the periostracum and the sculpture being similar. 

 They differ from B. ciliatum in the presence of the carina and in a 

 shghtly more recurved canal and slightly deeper groove behind the 

 canal. 



There is great variation in the weight of shells of equal size; some 

 shells are robust, others gradually tapered; some are strongly cari- 

 nated and angular, others scarcely carinated and are rounded, still 

 others have 3 carinae, and still others have one carina with one or 

 more strong cords; some have fewer, others more ribs than typical 

 specimens; and in some the bands of spiral striae are prominent and 

 sometimes separated by wide interspaces. 



Distribution: Point Barrow, Cape Prince of Wales, the Pribilofs, 

 the Aleutians, eastward to Cook's Inlet; the Kurile Islands. The 

 Point Barrow specimens extend the range into the Arctic to the 

 71st parallel. 



Buccinum plectrum Stimpson, 1865 



Plate 9, figures 11, 12 



Buccinum plectrum Stimpson, 1865, p. 374. — Martini and Chemnitz, 1883, ed. 2, 

 pi. 91, fig. 2.— Oldroyd, 1927, pt. 1, p. 239, pi. 5, fig. 5.— Morris, 1952, p. 122, 

 pi. 28, fig. 25. 



Approximately 40 live specimens and about 15 shells (in various 

 stages of decomposition), that were either empty or occupied by her- 

 mit crabs, were collected. One live specimen was taken on May 17, 

 1950, at a depth of 37 feet by means of a trap lowered through a 

 hole in the ice. All the other living specimens came from 16 stations 

 from depths ranging from 120 to 522 feet, the highest number, 13, 

 coming from the latter depth. In only three instances was there 

 more than 1 specimen from any station of less than 341 feet: 3 from 

 295 feet, 3 from 120 feet (Sept. 15, 1948), and 2 from 125 feet. The 

 largest shell was nearly 70 mm,, the largest living one about 60 mm., 

 and the smallest living one about 20 mm. in height. Foraminifers, 

 bryozoan colonies, and barnacles up to 8 mm. in diameter were present 



