492 MUKICIDJE. 



cula. I can say nothing of the branchial plume and reproduc- 

 tive organs, being unwilling to make a perhaps useless attempt 

 to see them by the destruction of the beautiful specimens. 



This very elegant creature inhabits the middle levels of the 

 littoral zone at Exmouth, in quiet sheltered pools amongst the 

 minor Algae, in company with the Cerithium reticulatum, (our 

 Rissoa vulgatissima,) which outnumbers it by fifty to one. 

 With it is also rarely found the Murex adversus of authors, 

 which we believe, when the animal is seen, will prove to be 

 congeneric with Rissoa vulgatissima. When our present animal 

 is just captured it is very lively, and creeps up a glass quickly. 



There can scarcely be a greater contrast than between this 

 animal and that of the Rissoa vulgatissima, with which it has 

 hitherto been confounded, and which has the entire aspect of 

 an elongated Rissoa, whereas our Murex tubercularis is an 

 undoubted Canalifer, though it has evident relations with 

 Eulima and Chemnitzia by the position of the eyes and shape 

 of the tentacula ; still the balance of characters is greatly in 

 favour of the present position. I believe Mr. Alder and 

 myself are the first and nearly contemporaneous observers of 

 this species. 



We believe the Cerithium metula of the ' British Mollusca' is 

 congeneric with Murex tubercularis above. But it is pos- 

 sible it may not be a muricidal animal : if so, it will probably 

 fall into the section of the elongated Rissoce. 



? M. METULA, Loven. 

 Cerithium metula, Loven. 

 , Brit. Moll. iii. p. 198, pi. 91. f. 3,4. 



Sectio VII. Testa gracilis, fusiformis, plicata, spiraliter striata. Canalis 

 ejfusus. Apertura subovalis, labio externo plus minusve emarginato. 

 Columella planato-substriata. Operculum nullum. 



MANGELIA, Leach, Forbes and Hanley. 

 M. GRACILIS, Montagu et auctorum. 



Mangelia gracilis, Brit. Moll. iii. p. 473, pi. 114. f . 4 ; (animal) 

 pi. R.R. f. 8. 



Animal spiral; ground-colour white, aspersed throughout 



