the Boat and Melon Volutes. 269 



in a generic sense in later times by Schumacher and Menke. In 

 the shells of the Boat Volutes the upper edge of the whorls is 

 produced into a ledge stretching outwardly or inwardly; in 

 the Melon Volutes, the upper edge of the whorls, with one ex- 

 ception, is coronated with erect or decumbent scales. Dr. Gray, 

 in a paper on Volutida in the ' Proceedings ' of the Zoological 

 Society for March 1855, states that the animal of the Boat Volute 

 is ovo-viviparous, " the young, when born, being of a large size, 

 and covered with a shell with a large irregular callous apex," 

 while the animal of the Melon Yolute is oviparous, " the eggs 

 being deposited in cartilaginous egg-cases like those of the other 

 zoophagous mollusks.^' These observations are doubtless well 

 founded ; and the shells show obviously enough that the mantle 

 of the animal is more developed and expanded in the Boats than 

 in the Melons. The correctness of this subdivision of ' Les 

 Gondolieres^ of Lamarck, as introduced by Mr. Broderip, is 

 thus supported by observations of the animal; and it remains to 

 consider the synonymy of the species, in which some errors need 

 to be amended. Mr. Broderip restricted the term Cymbium 

 (altered to Cymba) to the Boat Volutes, eight in number, and 

 founded a new genus, Melo, for the reception of the Melons, of 

 which there are nine species. Dr. Gray, instead of following 

 the nomenclature of Broderip, transferred the name C^jmbium 

 to the Melon Volutes, and introduced a new appellation, Yetus, 

 for the Boats, coined from the specific French name of Adan- 

 son, Le Yet. In the midst of this imbroglio of terms, I pro- 

 pose, in adopting the trinomial form of nomenclature, to use 

 the names Yettts and Melo in a subgeneric sense, under Cymbium 

 of the old conchologists taken generically. 



Genus Cymbium, Klein. 



Subgenus 1. Yet us. Gray. 



I. Cymbium [Yetus) Neptuni, Gmelin, Syst. Nat. p. 3467 ; Conch. 

 Icon. pis. 22 & 23. 



Valuta Neptuni, Gmelin. 



Neptuni (pars), Lamarck. 



Le Yet, Adanson. 



Cymba Neptuni, Broderip. 



Tritonis, Broderip. 



Yetus Neptuni, Gray. 



Cymbium olla, Lowe, fide Hanley. 



Hub. West Africa. 



Two species, well distinguished by Gmelin, with the names 

 Valuta Neptuni and navicula, were confounded together by La- 

 marck, and, excepting Dr. Gray, by all subsequent writers. 



