tlie Boat and Melon Volutes. 271 



Cymbium porcinum, Menke. 

 Yetus proboscidalis (pars). Gray. 



Hab. West Africa. 



Conchologists are divided in opinion as to whether this is a 

 distinct species, or merely a variety or young of the preceding. 

 Mr. Lowe, the latest authority on the subject, says (Proc. Linn. 

 Soc. 1860, p. 193), "Dr. Gray unites C. prohoscidale with 

 C porcinum, of which it may possibly prove, indeed, to be only 

 a large, mature or full-developed state or form ; but further ob- 

 servations of the shells and animals conjointly seem still requi- 

 site to justify such combinations.'^ In the face of this remark, 

 coming from so experienced an observer as Mr. Lowe, I have 

 kept the species distinct; but I must confess my inability to 

 make out more than one, in an early stage of growth. All the 

 very young and moderately advanced specimens, of which there 

 are many in collections, have the straight form and more di- 

 lated corona-ledge of C. porcinum, and it is not improbable, 

 therefore, that the attenuated contraction of the ends of the 

 shell of C. prohoscidale, like the callous overlaying and immer- 

 sion of the apex, may be the result of age. Still, specimens 

 of C. prohoscidale are known in a state which is apparently 

 scarcely mature; and all have an additional winding plait at the 

 base of the columella. Dr. Gray calls in question a remark 

 made by Mr. Adams in his ' Genera,' that this section of the 

 Cymbia have a deciduous nucleus. Mr. Cuming certainly pos- 

 sesses specimens of C. porcinum in which the nucleus, of a rude, 

 swollen growth, has been cast, still leaving a mammillary apex j 

 and he possesses also a specimen of a cast nucleus, with the 

 base almost walled-in, as it would be prior to being cast off. 



5. Cymbium {Yetvs) cisium, Lamarck, Anim. sans Vert. vol. x. 

 p. 380. 



Valuta cymbium, Lamarck (not of Linnaeus). 

 Cymbium excavatum (pars), Martini. 



cisium, Menke. 



Cymba cymbium, Broderip. 

 Cymbium cymbium, Adams. 

 Yetus cymbium. Gray. 

 Cymba gracilis, Broderip. 

 Cymbium gracile, Adams. 



Hab. West Africa. 



It is to be regretted that Mr. Broderip, Mr. Adams, and Dr. 

 Gray have followed Lamarck in assigning Linnseus's Voluta 

 cymbium to this species, notwithstanding the testimony to the 

 contrary given by Deshayes in a note to the species in his 

 edition of the * Animaux sans Vertebres/ It was the practice 



