Records of Dredging. 



191 



Art. VII. Records of the Results of Dredging. No. 3., Including 

 Notices of Species of Naticidce. By Edward Forbes, Esq. 



Two species of Natica occur on the Manx coast ; namely, 

 N. monilifera Lam. (the Natica glaucina of British authors) 

 and N. rufa Mont. The former is very frequent, the latter 

 rare : they are found on gravelly bottoms, at a depth of from 

 12 to 20 fathoms of water. I have examined the animals of 

 both, and do not recollect having met with any description of 

 them in print : as the results are interesting, and perhaps 

 important, I shall state them here. 



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Natica monilffera Lam. : a, a side view of the extracted animal; b, a front view, the tentacular 

 hood and mantle reflected ; c, a front view of the head j d, a view of the head from beneath, 

 showing the foot-like process ; e t one of the cartilaginous jaws ; /, the operculum. The figures 

 are all larger than the parts that they represent. 



The head of the N. monilifera resembles a produced 

 tubercle, is of a pink colour, and presents, in front, a pear- 

 shaped opening, placed vertically, which is the mouth. From 

 the centre of the mouth slightly protrudes the anterior part 

 of the jaws, with the apex of the tongue between them. 

 These jaws are cartilaginous, of a square form and consider- 

 able size, toothed in front like a saw. The tongue resembles 

 that of a Littorina [VIII. 75.], but is shorter and broader 

 in proportion. Beneath the head, and attached to it only, is 

 a process resembling a little foot. The mantle is pinkish 

 white, and presents nothing remarkable in its form : beneath 

 it is a sort of hood, produced at one side into a broad trian- 

 gular tentaculum, which is pinkish white at the base, and 

 brown towards the apex, but presenting no appearance of an 

 eye. I have examined six animals, and never found more 

 than one tentaculum. The foot is dilated ; of a pinkish white 

 colour, with the sides variegated with brown. The oper- 

 culum is thin, corneous, and of a pale brownish yellow colour. 



The animal of N. rufa is white, with the exception of a 

 fine thread-like line of dark brown, which borders the much 

 dilated foot. It has no eyes, and is furnished with two lan- 



p 4- 



