462 Mr. W. Clark on the Conovulidse, 



anterior margin of the aperture, but from its tenuity and lustre 

 are easily observed; they are very rarely exserted beyond the 

 limits of the shell, and are fixed at the centres of the bases of the 

 tentacula; they are mounted on minute orange- coloured emi- 

 nences. The foot is small, short, seldom extended beyond the 

 basal whorl, truncate and auricled anteriorly, very moderately 

 acuminated behind ; the sole in front is separated from the upper 

 skin by a groove, forming double labia, and carries on the oper- 

 culigerous lobe a thin, light horn- coloured flexible suboval ob- 

 liquely striated operculum ; the anterior upper margin of the 

 foot is bordered by two linear segments of a circle with the con- 

 vexity outwards, but indented in the middle, of a bright orange- 

 yellow, but these colours intensely marked are only observable in 

 adult specimens, the younger ones being white ; it has been 

 omitted to state, that several portions of the foot are more or less 

 tinctured with orange-yellow. The verge of this species springs 

 under the right tentaculum ; it is rather long, pale yellow, flat 

 and strap-shaped for two-thirds of its length, and at the end it 

 becomes more spread and falcate, with two short orange- coloured 

 stripes at the terminus, where the orifice is placed. The testis 

 is an elongated oval yellowish lobe, situate in the posterior volu- 

 tions, and communicating with the verge by a long wrinkled 

 tortuous filiform vas deferens or epididymis, like that of Buc- 

 cinum undatum ; it is at least 2~ inches, or three times the length 

 of the shell. The tongue is also of extraordinary length, flat, 

 strap-shaped, and without a spinous armature. A single branchial 

 plume in the usual place, small, narrow, of twelve to fifteen short 

 coarse strands, with an arterial or branchial vein in the centre ; 

 indeed we are not quite sure that the plume is not double ; the 

 colour is pale drab. We have not observed an incipient fold of 

 the mantle, but whether it be there or not, we have sufficient evi- 

 dence of an approach to the Muricidal tribes; and after, in another 

 memoir, we have given some notes on Scalar ia, Coriocella, Ve^ 

 lutina and Natica, our scheme of natural order from the BuUidce 

 to the Muricidal families will be sufficiently developed. 



It is scarcely doubtful that the E. nitida is a mere variety of 

 the type, E. polita, and the two varieties of E. distoj'ta are the 

 young. The E. polita is lively, not at all shy, and inhabits the 

 coralline zone at Exmouth in abundance. The other acknow- 

 ledged British species are the E. suhulata and E. bilineata, but 

 their distinctness admits of doubt, and it is by no means certain 

 that when the animals are better known, some of the more polished 

 elongated Chemnitziae may not be transferred to the Eulimoi. 



Aclis (n. g.), Loven. 

 This genus contains only two very rare British species, the 



