276 GASTEROPODOUS MOLLUSCA OF BERWICKSHIRE. 



brown colour, speckled with a few irregular reddish and yellow dots, 

 duskier in the centre, the margin of the cloak widely overlapping the 

 foot, deeply sinuated in front, and with an obscure emargination behind. 

 The head is truncate with two white awl-shaped tentacula, which are 

 contractile and originate in the anterior angles, having the eyes, which 

 are black and very distinct, at their external bases. The mouth is ter- 

 minal, furnished within the fleshy lip with small cartilaginous jaws, and 

 a long, narrow, linear, or riband-shaped tongue, roughened with spinules 

 arranged in regular series. Above the head, and under the cloak, there 

 is a large slit which leads to the branchial cavity, and the water of re- 

 spiration is conducted to this wide orifice by a short canal formed by a 

 fold of the cloak ; and it is this fold which produces the frontal sinuation, 

 for there is really no interruption in the margin of the cloak. Within 

 the cavity there lies retroflected the male organ of generation, which 

 seems very large in proportion to the animal : it is somewhat compressed, 

 obtuse, with a long point directed backwards. Foot oblong, truncate in 

 front, where it is opaque milk-white, the rest of it being watery white. 

 The space between it and the cloak is more or less tinted with black or 

 violet. 



The shell is concealed and embedded in the cloak, occupying a dorsal and 

 central position. It is three lines broad and about five long, ear-shaped, 

 convex, milkwhite, even and apparently smooth ; but, when looked at 

 through the magnifier, it is seen to be wrinkled by the lines of growth ; 

 spire depressed, small, consisting of a single whorl ; aperture very patu- 

 lous, oblong, the inferior margin somewhat truncate, the pillar lip flat- 

 tened, and continued in a spiral form within the shell. 



The creature creeps very slowly, and, when in progression, raises itself on the 

 foot, while, at the same time, the tentacula are extended to the utmost, 

 and protrude beyond the margin of the cloak : when at rest, they are kept 

 concealed under this their penthouse. It swims easily in a reversed 

 position at the surface, the foot being then made slightly concave. The 

 form of the foot is variable ; for sometimes the animal will expand it 

 until it becomes almost circular, or extend it until it forms an oblong 

 square obtusely pointed behind. When alarmed, the body is contracted 

 so that the edges of the cloak meet together on the ventral aspect, and 

 the foot is greatly narrowed. The eyes are proportion ably large, and are 

 visible from below, shining through the transparent skin. 



