WOODWARD : ANATOMY OF VOLUTA, ETC. 121 



The nervous system (Figs. 11, 13, and 14) of JYeptuneopsis closely 

 accords with the volutoicl type, differing from the latter only in being 

 slightly less compact ; thus the commissure connecting the supra- 

 intestinal ganglion with the right pleural is slightly longer than in 

 Voluta ancilla, and in a similar way the sub-intestinal ganglion is less 

 completely fused with the pleurals. In this respect JYeptuneopsis is 

 somewhat intermediate between Voluta ancilla and Melo JYeptuni as 

 described by Bouvier. 



In the t-hort summary of the anatomy of the form which I supplied 

 to Mr. Sowerby, and which was published in his original description 

 of this genus, I state that the nervous system of JYeptuneopsis differed 

 considerably from that of Voluta. In making the comparison I was 

 labouring under the belief that Bouvier had described a true Volute, 

 instead of a member of the genus Melo. This correction removes the 

 only point of difference between the internal organs of JYeptuneopsis 

 and of Voluta, if the form I have described, V. ancilla, be typical of 

 this genus. 



3. VOLUTILITHES ABTSSICOLA (Ad. & Eve.). 



External characters. — The head is slightly compressed dorso- 

 ventrally, and divided anteriorly by a deep median cleft (Fig. 8) ; 

 these two anteriorly placed headdobes are intimately related to the 

 opening through which the introvert is protruded ; at first sight they 

 might be thought to represent the lips, but this is not the case, the 

 true lips being situated with the mouth at the extremity of the 

 introvert. Each head-lobe is deeply grooved on its outer border, and 

 the inferior margins of these grooves meet ventrally behind thl< false 

 mouth, in such a manner that these false lips form a V-shaped 

 thickening on the under side of the head (Fig. 8b). The tentacles 

 are stout, and related to the upper margins of the grooves in the 

 head -lobes. Behind each tentacle is a short but very stout eye-stalk, 

 bearing a prominent eye on its distal extremity. 



The foot is very large, and probably capable of great expansion. 

 There is no operculum. The siphon is long and devoid of appendices. 

 The edge of the mantle is bordered by a single row of low papilla?. 



The pallial complex is in most respects like that of Voluta ancilla or 

 of JYeptuneopsis (cf. Figs. 1, 3, and 4). The gill and dark-coloured 

 osphradium, being identical in structure, and the anal, genital (9), 

 and excretory orifices, are similar in position. The only difference, 

 however, is a striking one, and is due to the entire absence of the 

 characteristic hypobranchial gland, a structure present in the majority 

 of the Bhacbiglossa. 



The alimentary canal. — The buccal mass and radula-sac form 

 a stout muscular mass, occupying the greater part of the introvert 

 (Figs. 4 and 5). As in Voluta, two pairs of pre-neural salivary 

 glands are present ; one large, branched and whitish pair opens into 

 the oesophagus at its junction with the buccal mass, while the second 

 pair is tubular and yellowish, and unites to form a fine duct, which, 



