52 



PROCEEDINGS OF THE MALACOLOGICAL SOCIETY. 



The surface of the animal is slightly crinkled, but otherwise smooth. 

 The parapodia are moderately developed, but do not cover the mantle ; 

 posteriorly they are united where they meet the foot, the depth of the 

 union being about 3 mm. The mantle is large ; its free right-hand 

 border is turned down for about 4 mm., and posteriorly is suddenly bent 

 to the left to form a short wide siphon 5 mm. in length. The shell- 

 sac is completely closed, but a minute hollow papilla, near its centre, 

 indicates the position where the opening should be. 



The rhiuophores are short, cylindrical, and blunt. Their apices are 

 hollowed out, the margins of the cavity being irregular. The anterior 

 tentacles are small, and, as usual, are formed by scrolled projections of 

 the buccal lobes. The latter are large and of circular form. 



The eyes lie 2-5 mm. in front of, and slightly lateral to, the 

 rhinophores. 



The anal orifice lies as usual in the siphon. Tlie genital opening is 

 situated beneath the mantle on a level with the anterior limit of the 

 gill, at a distance of 12 mm. from the anterior ends of the parapodia, 

 and 4 mm. in front of the large single opening of the opaline gland. 

 The genital groove takes the usual course to the penis beneath the 

 right anterior tentacle. 



Fig. 2. 



Fig. 3. 



Fig. 4. 



The animal is greenish grey, covered with a network of fine 

 irregular black reticulations, which in places run together to form 

 blotches, or more fre(]uently somewhat vague ring-like markings. 

 These are sharply circumscribed, as a rule, towards the centre, but 

 outwardly fade off into the general reticulation. The rings are 

 scattered chiefly upon the sides of the body and upon the outer surface 

 of the parapodia, the blotches being mainly situated near the margin 

 of the foot, a specially definite one marking the upper surface of its 

 posterior free extremitj'. The inner surface of the parapodia is marbled 

 with large confluent black blotches. The surface of the mantle is also 

 marbled, but verj' delicately, the depressed free edge being somewhat 

 specially pigmented. The sole of the foot is yellower than the rest of 

 the body-surface, and is sparingly flecked with small blotches of black 

 or brown. 



The shell (Figs. 2, 3) is rather long, narrow, and flat (24 by 16 by 

 2'0 mm.). It is slightly calcified, showing internally traces of nacre. 



