ACHATINELLA. 
Plate I. 
Genus ACHATINELLA., Sicainson. 
Testa parviuscula, conica, aut sinistrorsa aut dextrorsa, 
baud umbUicata, anfraclibus plerumque sex ad septem 
et leevibus, columella brevi , late appressa, callosa et 
sapissime coniortd, aperturd parviuscula, labro sim- 
plici, interdum subincrassato, nunquam rejlexo. 
Shell rather small, conical, either sinistral or dextral, not 
umbilicatecl, 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 substance, they are characterized 
by the same plan of convolution, of from six to seven 
whorls, never umbilicated, by a similar vivid design of 
colouring, 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 Glandina 
division of the Achatince, and might be appropriately re- 
moved hence. 
The generic character of Achatinella was observed about 
the same time by Swainson in England, and by Ferussac 
in Prance ; 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 Achalinellce 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 Achatinellce were known to Linnmus ; 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. lugubris, 
referred to the same marine genus. Lamarck had no more 
May, 1850. 
acquaintance with the Achatinellm 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 seminigra 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. Pfeiffer, there are some points in which I 
find occasion to differ from him. A. bicolor. Jay, does 
not participate in the essential characters of the genus, 
and is referred to Achatina. A.plicata is a very abnormal 
form, having little if any indication of the callous twisted 
columella, whilst it is of a different substance from the 
rest of the species, and the only one with any external 
raised sculpture, but this I have allowed to remain ; as 
also the three homy species already mentioned partaking 
of the Glandina type. A. Bulimoides, Swainson, is dis- 
tinct from A. lorata, Ferussac, and both differ essentially 
from A. mustelina, Mighels. A. Stewarti cannot be safely 
regarded as a variety of A. vulpina, nor is Swainson’s 
A. perversa identical with Ferussac’ 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 Achalinellce are confined to the Sand- 
wich Islands, where they represent the Achatince or 
Bulimi of the continent. 
Species 1. (Mus. Cuming.) 
Achatinella nubilosa. Achat, testa ovato-oblongd, 
dextrorsa, anfractibus rotundatis, longitudinaliter pli- 
cato-striatis, ad suturas leviter crenulatis, columella uni- 
plicata, plied compressd, marginali ; carneo-stramined, 
flammis nigricante-olivaceis irregulariter striata et re- 
ticulata, apice rubente-fused, apertures fauce albicante. 
The clouded Achatinella. Shell ovately oblong, 
dextral, whorls rounded, longitudinally plicately stri- 
ated, slightly crenulated at the sutures, columella 
furnished with a single compressed marginal plait ; 
