CLASS GASTROPODA 
69 
cus; whorls two and a half to three, the last very much the largest, in¬ 
flated ; suture distinct, the epidermis sometimes wrinkled close to it; nucleus 
polished; aperture wide, oblique, rounded, the upper end of the columella 
and the anterior end of the outer lip approximated, united by a thin glaze 
of callus; interior polished, brown; base of the aperture rounded, columella 
arcuate; umbilicus small, narrow, marked by raised wrinkles of epidermis, 
which sometimes give it a carinated aspect from their abrupt cessation at 
the umbilical margin; base of the shell smoothly rounded; earlier whorls 
darker colored than the last. Alt. of shell, 10.0; of aperture, 7.0; maximum 
lat. of shell, 13.8; of aperture, 7.0 mm. (Dali.) 
Type in United States National Museum. Type locality, Pribilof and 
Aleutian Islands. 
Range. Known only from type locality. 
Genus AQUILONARIA Dali, 1886 
Shell lioplaciform, more or less membranous, thin, imperforate, without 
sculpture, but with a rough, transversely shaggy epidermis. Operculum 
subspiral, with a raised subspiral rib on the inner side. (Dali.) 
Type. Aquilonaria turneri Dali. 
Distribution. Arctic Ocean, Labrador. 
Aquilonaria turneri Dali, 1886 
Proceedings of the United States National Museum , 9:204; PI. 3, figs. 1, 2, 3. 
Shell globose-conic, with five and a half full and rounded whorls 
regularly increasing. Shell substances white, extremely thin, and wanting 
near the aperture; covered with a thick, shaggy, more or less hairy, trans¬ 
versely rugose epidermis of a brownish color, of which the outer and 
anterior margins of the aperture are chiefly formed. This is tough and 
flexible in life, but dries out of shape when dessicated; sutures with a 
narrow channel except in the last whorl where the channel gradually 
becomes obsolete; last whorl forming more than two-thirds of the shell; 
aperture ovate, margin thin, not reflected; columella smooth, thin, round¬ 
ing gradually into the anterior margin; inner lip without callus; base 
rounded, full, without any trace of an umbilicus. Operculum thin, brown¬ 
ish, with about three whorls, slightly transversely undulate and longitudi¬ 
nally finely striate; on the inner side a well-marked raised rib gyrates with 
the whorls near their inner edge, but does not quite reach the anterior 
margin of the operculum. Maximum long, of shell, 14.25; of last whorl, 
11.00; of aperture, 7.00; of operculum, 7.00 ; maximum lat. of shell, 10.00; 
of aperture, 6.00; of operculum, 5.00 mm. (Dali.) 
[ 671 ] 
