Montana Field Guide

A moderately large slug of about 45 mm extended, but may reach 65 mm. As with all species of Hemphillia, the shell is partly exposed through a slit on the mantle about one-third its length, the mantle elevated into a visceral hump and covered with papillae. Dorsal base color is dark brown or dark gray, sometimes nearly uniformly so, and sometimes yellowish-gray to cream with numerous irregular dark markings; head coloration is dark brown or dark gray. The pneumostome is posterior to the midline of the mantle on the right side. The foot is narrow, with a median groove and tail pore near the posterior end, but lacking a dorsal keel. The sides of the foot with a uniform series of prominent oblique grooves, the sole is undivided (not tripartite); the mucous typically is clear. Sometimes responds to disturbance by thrashing the foot side to side and flipping themselves (Hendricks 2012, Burke 2013). Internal anatomy is described by Vanatta (1914) and Pilsbry (1948).

An elevated mantle in a hump, and presense of mid-dorsal mantle slit (sometimes exposing internal shell) separate the genus Hemphillia from other Montana slugs. Presence of small papillae on the mantle, a blackish to tan coloration, and a relatively narrow tail with poorly-defined or absent mid-dorsal stripe help differentialte this species from H. camelus.

No information.

Mostly in mesic mixed conifer forest, typically near water such as stream-side riparian areas and seeps. Canopy species include Engelmann spruce, subalpine fir, western redcedar, western hemlock, grand fir, Douglas-fir, alder, aspen, and black cottonwood. Usually found under woody debris and leaf litter or in downed rotten logs, sometimes under rocks (Hendricks 2012).

No information.

It has been reported three times in the stomachs of terrestrial gartersnakes (Thamnophis elegans).

Animals found in the wild as juveniles have lived more than 16 months in captivity.

Habitat occupied by Hemphillia danielsi (moderate elevation mixed conifer forest, often near water) is threatened by logging, grazing, fire, and possibly weed control and rural home development. The impact of fire retardant on this and other terrestrial mollusks is not known. Little is known about this species, including its sensitivity to disturbance (Frest and Johannes 1995; Hendricks 2003).