ACHATINELLA. 



Genus ACHATINELLA, Swahmn. 

 Testa parvimcnla, conica, aut s'mistrorsa aut dextrorsa, 

 hand umbilicata, anfractibus plermnque sex ad sepiem 

 et lavihus, columella brevi, late appressa, callosa et 

 saphsimi contortd, aperturd parvlusculd, labro sim- 

 plici, biterdmn sitbincrassato, nuiiqicam rejlexo. 

 Shell rather small, conical, either sinistral or dextral, not 

 umbilicated, whorls generally six to seven in number 

 and smooth, columella short, broadly appressed, 

 callous and mostly twisted, aperture rather small, 

 lip simple, sometimes rather thickened, never re- 

 flected. 

 The gaily painted shells which form the subject of 

 the present monograph have an especial claim to the 

 honour of being ranked as a genus. They are nearly all 

 of an uniform size and sijbstance, they are characterized 

 by the same plan of convolution, of from six to seven 

 whorls, never umbilicated, by a similar vivid design of 

 colom-ing, and by a peculiarly callous twisted plicate 

 structure of the columella ; the genus is, moreover, confined 

 to one particular isolated locality, the Sandwich Islands. 

 An exception must, however, be made in part to these 

 remarks, in reference to three small horny species, A. cla- 

 rus, pyramis, and corneola, placed in the genus by Dr. 

 Pfeiffer, which are more nearly allied to the Glaiidim 

 division of the Acltat'uia, and might be appropriately re- 

 moved hence. 



The generic character of AchutineUa was observed about 

 the same time by Swainson in England, and by Fcrussac 

 in France ; the former in his descriptions and figures of 

 new species in the ' Zoological Illustrations,' and the 

 latter in a plate devoted to the few species then known 

 to him, towards the close of his great work on the terres- 

 trial mollusca. The Achafiiiella were also noted in the 

 United States about the same period by Professor Green, of 

 Philadelphia, in a short memoir communicated to the Mac- 

 lurian Lyceum of that city ; and some important species 

 were subsequently contributed by Professor Mighels and 

 Dr. Gould, of that rising seat of scientific learning, Boston, 

 Massachusetts. 



None of the Achathiella were known to Linnanis ; nor 

 even to Chemnitz, until the completion of his great work. 

 In the last plate of the Conchylien Cabinet there is a 

 figure of A. perversa, under the generic name of Turbo, and 

 in a plate just preceding that, is a figure of A. lugtibris, 

 referred to the same marine genus. Lamarck had no more 



Mav, 



acquaintance with the AchatinelltB than Chemnitz. The 

 same species which came under the observation of 

 Chemnitz, A. lugubris, was observed by Lamarck, who, 

 supposing it, like him, to belong to a mollusk of salt-water 

 habits on account of its polished substance, referred it in 

 error to the same marine family, independently of any 

 knowledge that his Monodonta semin'ujra and the Turbo 

 lugubris of the Conchylien Cabinet were one and the 

 same thing. 



In the valuable monograph of this genus lately pub- 

 lished by Dr. Pfeifl'er, there are some points in which I 

 find occasion to differ from him. A. bicoJor, Jay, does 

 not participate in the essential characters of the genus, 

 and is refen-ed to Achatina. A.pUcata is a very abnormal 

 form, having little if any indication of the callous twisted 

 columella, whilst it is of a ditt'erent substance from the 

 rest of the species, and the only one with any external 

 I'aised sculpture, but this I have allowed to remain ; as 

 also the three horny species already mentioned partaking 

 of the Glandina type. A. BuUmoides, Swainson, is dis- 

 tinct from A. lorata, Eernssac, and both dLB'er essentially 

 from A. miistelina, Mighels. A. Steicarti cannot be safely 

 regarded as a variety of A. vidpina, nor is Swainson's 

 ../. perversa identical with Fcrussac's A. decora. The 

 species are extremely variable throughout in colour, but 

 it is important not to throw too many of them together on 

 this account, whilst each, regarded strictly, appears to be 

 characterized by regularity of form and general unity of 

 design. 



As already noted in regard to the geographical position 

 of the genus, the AcUalinelhe are confined to the Sand- 

 wich Islands, where they represent the Achatina or 

 BuUmi of the continent. 



Species 1. (Mus. Cuming.) 



ACHATINELLA. NUBILOSA. Achat, testa omdo-oblougd, 

 dextrorsa, anfractibus rotundatis, longitudinaliter pli- 

 cato-striatis, ad suturas leviter cremlatis, colmrielld uni- 

 plicatd, plica compressd, Tmrginali ; carueo-stramined, 

 Jlammis tdgricante-olivaceis irregulariler striata et re- 

 ticidatd, apice rubente-fusod, aperturee fauce albicante. 



The clouded Achatinella. Shell ovately oblong, 

 dextral, whorls rounded, longitudinally plicately stri- 

 ated, slightly crcnulated at the sutures, cohunella 

 furnished with a single compressed marginal ]ilait ; 



