INVERTEBRATE PALAEONTOLOGY. 329 



VANIKORIDiE. 



Genus VANIKORO. Quoy and Gaim. 



Synon.— Vcmikaro, Qnoy and Gaimard (1832), Voy. Astro]., Zool., II, 239.— H. and A. Adams (1854), Gen 



Recent Moll., I, 374.— Meek (1804), Smithsonian Check-List N. Am. Cret. Fossils, 18.— 



Stoliczka (1868), Pala?oiit. Indica, II, 307. 

 Merria, Gray (1839), Beechey's Voy., Zool., 137. 

 Momia, Gray (1840), Synon. Moll. Brit. Mus., 124. 

 Leiiculin, Swaiuson (1840), Malac, 346. 

 Nqriea, Recluz (MS.), d'Orbigny (1841), Moll. Cub., 39; and (1843) Pal. Fr., II, 170.— Re"cluz 



(1844), Rev. Zool., 4 and 49.— De Koniuck (1844), Terr. Anthr., 474— Geiuitz (1845), 



Grundr. d. Verst., 341.— Chenn (1859), Man. Conch., I, 331. 



EUjm. — Vanikoro, the name of one of the Pacific islands. 

 Type. — Xcrita vancellata, Gmcliu. 



Shell subglobose, thin or moderately thick, in the recent state often 

 covered with a velvety epidermis; volutions few, last one large; surface 

 ribbed, cancellated, or spirally striated; inner lip moderately thickened or 

 rather thin, simple, and slightly rerlexed ; columella excavated or slightly per- 

 forated, the umbilical opening usually ending in an arched channel behind ; 

 aperture varying, according to the species, from semilunar to subovate, but 

 generally somewhat modified by the body-volution. 



The shells of this genus are usually rather thin, subglobose, and, in 

 recent examples, white. Some species have distinct, regular, vertical costa% 

 while others have only revolving striae and furrows The genus seems to 

 have been first proposed by its authors as a section of Velutina, to include 

 cancellated species from the Pacific islands. Nearly all later authors, 

 however, admit it as a distinct genus; though the. name Narica has been 

 most generally used for it. The laws of priority, however, require that we 

 should go back to the older name Vanikoro, notwithstanding the fact that it 

 was only proposed as a subgenus, and subsecpieutly, I believe, altogether 

 abandoned by its founders; for the fate of a generic or subgeneric name, 

 once regularly proposed, does not depend on the later opinions of the author 

 proposing it, but on the fact whether or not its type represents a good new 

 genus. 



It seems very probable that this genus existed as far back as the 

 Triassic epoch; and we also find forms agreeing quite nearly with it in the 

 Jurassic and Cretaceous rocks; also, a few in the Tertiary. Some twenty to 

 thirty living species have likewise been described by conchologists from our 

 existing seas, and there arc doubtless a number of others yet unknown. 

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