Shell. A conical shell with a. rather tall spire but not much drawn out basally. It is slightly transparent and glossy in its younger parts and these are also slightly opalescent. It is rather variable in its characteristics: the apical angle ranges from 50-60° and the degree of angulation of the profile of the spire may be marked or very slight. There are 5-6 whorls which are swollen, the sutures deep and incised, placed well abapical of the periphery of the upper whorl. The ornament comprises costae, spiral ridges and growth lines, the last numerous and distinct, appearing as small upstanding ridges crossing the spiral ridges, lying along the costae and filling in the hollows of the cancellation due to the last two features. They are very prosocline near the adapical suture in each whorl but become orthocline at the periphery. The costae show the same curvature, die out at the periphery and also near the outer lip. They are undulate in section and about equal in breadth to the intervening spaces. They vary in number from 12-18 on the last whorl (depending on the extent to which they disappear near the aperture), 15-20 on the penult, dropping in more adapical whorls. The spiral ridges are steep-sided, narrower (usually) than the intervening spaces which vary much in breadth. Beneath each suture is a ramp normally without ridges in the older whorls but often with 1-2 in younger ones. The spiral ridge marking the end of the ramp is often prominent as are the next 2; in this event the whorl is distinctly angulaled. There may be 15-22 ridges on the last whorl, 5-8 on the penult, then 4,3,2 on successive more adapical ones. Ridges and costae form low tuberositys where they cross, and a squarish reticulation of which the hollows are crossed by growth lines.
The protoconch has 1.5 whorls with a smooth or punctate surface. It measures 1100-1200 µm across, and 1100 pan in height.
Aperture. Oval, angulated above and drawn out below into a short and broad siphonal canal from which it is hardly distinct. It lies in a gently prosocline plane and is surrounded in older shells by a peristome. The outer lip arises at the level of spiral ridges 7-8 on the last whorl more or less at right angles lo the axis of the spire. Ii follows an approximately semicircular course to the distal end of the siphonal canal with little or no change of direction to mark the origin of the canal. The columella lies straight in the axis of the spire and shows 2 or more low spiral folds. The lip is turned out considerably, its edge joined to the last whorl but leaving a groove below a siphonal fasciole and a small pseudoumbilicus. The inner lip may form a thin layer over the last whorl, obscuring its ornament. The lip and the columella bear innumerable minute projections. The siphonal canal is broad and widely open, twisted a little to face towards the outer lip and its lip raised above columellar level. In young shells the outer lip and siphonal canal are thin, the columellar folds arc absent and the inner lip docs not spread over the last whorl.
Colour. White lo yellowish brown, sometimes with a slight greenish tint.
Size. Up to 15 x 8 mm. Last whorl = 60-75% of total shell height; aperture = 40-50% of shell height.
Animal. There is no snout, the tentacles arising from the edge of a transverse fold on the underside of which lies the small opening of a proboscis sac. Each tentacle is finger-shaped, blunt at the tip and bears an eye on its outer side about a third of its total length from the base. The basal third is thicker than the rest of the tentacle which narrows suddenly beyond the eye. The mantle edge
The foot is broadly curved anteriorly with markedly recurved anterolateral points behind which its breadth decreases and then expands. Us anterior end is double, and it tapers to a blunt point
Colour, While-cream; eyes brown-black, some orange colour in the visceral hump.
Geographical distribution. This is an arctic species, probably circumpolar which stretches south to the northern borders of the North Sea and to Massachusetts; British specimens are probably subfossil.
Habitat. On soft bottoms from a few metres lo 1000 m depth, the greater depths in the south of its range.
Food. The animals are said to eat ophiuroids.

Admete couthouyi: About 75 specimens (labeled A. middendorffiana) from localities ranging from Dcase Inlet south to Nunivak Island, Alaska were examined; Further about 80 specimens (labeled A. couthouyi) from localities ranging from the Sea Horse Islands, Alaska, to Point Loma, Calif.; about 30 specimens (labeled A. couthouyi) from localities ranging from Labrador, Newfoundland, and Maine to Massachusetts; and 12 specimens from Finmark and Vads0, Norway.
Time did not permit the exhaustive study necessary for determining with absolute certainty that A. middendorffiana is merely a variety or form of A. couthouyi but it is reasonably certain. Grant and Gale (1931) consider A. middendorffiana a low-spired form of A. couthouyi. Certainly there are many individuals that could as easily be assigned to one as the other species. If these are distinct species, as seems highly doubtful, then there are specimens of A. middendorffiana on the East Coast. A specimen from the Gulf of Maine has very weak axial ribs, is somewhat tumid, and has spiral sculpture resembling that of A. middendorffiana. Another specimen from Newfoundland has the short spire and tumid body of A. middendorffiana, but with the ribbing and spiral sculpture more closely resembling those of A. couthouyi. Six specimens from Labrador are all characterized by weak axial ribbing, but four of them have a long spire and the other two have a short spire and are somewhat tumid. Some of the specimens from the West Coast that are labeled A. couthouyi have weak ribs, a short spire, and flat, spiral bands with narrow interspaces. Others from the same locality have the axial ribs almost lacking, a long spire, and narrow spiral cords with interspaces wider than the cords.
There are all combinations of short to long spires, slenderness to obesity, axial ribs varying from prominent and sharp to those scarcely perceptible at the sutures, and of narrow spiral threads with wider interspaces to flat, spiral bands with interspaces narrower than the bands.
Several specimens from off southern California have prominent axial ribs and spiral cords that cause the shells to be nodulous. All of the specimens from Norway have a long, pointed spire, and the majority are nodulous. The specimens from the east coast of North America tend to be smaller than those from the Alaskan Arctic.

Admete couthouyi: Admete couthouyi is circumpolar: it has been reported from north of Alaska, Canada, Europe, and Siberia, and from many of the major northern islands. It occurs from Alaska south to southern California and to Japan; from Baffin Bay and Greenland south to New England; and from Spitzbergen south to the Faroes.