22 A Canadian Arctic Expedition, 1913-18 



The species is perhaps nearest to P. esychus Dall, from the same region, in 

 which the spire is proportionately longer, the whorls more inflated, and the 

 spiral sculpture less coarse. 



It is named in honour of Mr. Frits Johansen, naturalist of the expedition, 

 and to whose energy the larger part of the collection is due. 



(Icnus VgUitopsius Morch. 

 Volutopsius stefanssoni, n. sp. (PI. I). 



Shell large, heavy, rude, pinkish brown with a rosy protoconch and five 

 rapidly enlarging whorls; nucleus swollen, large, irregular, of about two whorls, 

 blunt at the apex; suture distinct, not channelled; whorls inflated, with a high 

 rounded shoulder and five or six obscure swellings at the shoulder which do not 

 become definite ribs; there is no spiral sculpture, but the lines of growth are rude 

 and occasionally lamellose, especially toward the aperture in senile individuals; 

 canal short, wide, slightly recurved; aperture wide, the outer lip thickened but 

 hardly reflected, throat whitish; body in the mature shell with a layer of whitish 

 enamel which extends to the end of the pillar, which is arcuate, shorter than the 

 aperture and obliquely truncate in front. Height of shell 114; max. diameter 65; 

 height of last whorl 87; of aperture 75 mm. 



Station 24. Point Barrow, Alaska, sandspit. Also collected by the U. S. 

 Bureau of Fisheries at various stations from the Pribilof and Nunivak islands, 

 Bering sea, northward to the Arctic ocean, in 25 to 56 fathoms. Catalogue 

 4128 (Ottawa). 



Three fragmentary or immature specimens were obtained by the expedition 

 at Point Barrow; a description has been prepared from an adult in the collection 

 of the U. S. National Museum. The shells, as in many other species, some- 

 times show narrow oblique or zigzag ridges due to some cause not yet determined, 

 but probably abnormal. The species in a general way recalls V. castanea Morch, 

 a much smaller species common on the Aleutian islands. The species is named 

 in honour of the commander of the Canadian Arctic Expedition. 



Genus Margarites Leach. 

 Margarites ecarinatus, n. sp. (PL II, figs. 5, 6). 



Shell pinkish grey, depressed, with about five rapidly enlarging whorls; 

 nucleus minute, glassy; subsequent whorls moderately inflated, separated by a 

 deep but not channelled suture, having a rounded periphery, a wide, completely 

 pervious umbilicus, and a large, very oblique, iridescent aperture. Axial 

 sculpture of very fine silky incremental lines; spiral sculpture of low flattish 

 threads separated by narrower interspaces sometimes carrying a finer intercalary 

 thread; this sculpture is carried over the base but is absent from the walls of 

 the wide umbilicus; aperture rounded, very oblique, the margins sharp, hardly 

 meeting over the body except by a thin layer of enamel. Operculum brown, 

 thin, multispiral. Height of shell 8; max. diameter 15 mm. Catalogue No. 4071 

 (Ottawa). 



Station 22, in N. Latitude 69 35' and W. Longitude 163 27', dredged in 

 11-12 fathoms, sandy bottom, 1 specimen. Also represented in the U. S. Nat. 

 Museum by specimens collected in Bering sea, among the Aleutian islands, and 

 as far to the east and southward as Port Althorp, Alaska. 



This species is nearest to M. vorticiferus Dall, which has about the same 

 range, but presents constant differences. In vorticiferus the spire is more elevated 

 and the whorls flattened and carinate at the periphery; the spiral sculpture is 

 generally finer and the axial sculpture coarser. Its measurements are: height 15; 

 max. diameter 20 mm. 



