130 
shells to which it is affixed, by inequalities in the form and surface 
of the shell, than by any real attachment of the substance of the shell 
itself, for the attached valves are covered with a continuous periostraca. 
As all attached shells have a free young state, as may be seen by 
examining the umbones of Arcinella, Chama, and other attached bi- 
valves, the young of Etheria are doubtless free, and there is nothing 
peculiar in the young of Miilleria being free; but there is a great 
peculiarity in the young shell becoming united imto a tubular case, 
and one of the valves, after the other has become attached, separating 
itself from its younger part by a natural caries.or crack. 
June 27, 1854. 
Dr. Gray, Vice-President, in the Chair. 
The following papers were read :— 
1. Descriprions oF THIRTY-NINE New SPECIES OF SHELLS, 
FROM THE COLLECTION oF HuGuH Cuming, Esa. 
By Artuur Apams, F.L.S., &c. 
(Mollusea, Pl. XXVIII.) 
1. Votva rosea, A. Adams. (Pl. XXVIII., fig. 9.) V. testa 
elongata, medio ventricosa, ad extremitates attenuata, coarctata, 
rectiuscula, rosea, albo-varicosa, levi, dorso fascia angusta, trans- 
versa, albida ornato, labio in medio ventricoso, ad extremitates 
subrecurvo, labro crasso, antice angulatim arcuato, ad canalem 
emarginato. 
Hab. China. Mus. Cuming. 
Like V. birostrata, but is more slender, and more attenuated poste- 
riorly, and wants the spiral fold on the hind part of the inner lip ; 
the anterior beak is straight and not recurved, and the marginal varix 
of the outer lip is thinner. 
2. AMPHIPERAS MARGARITA, A. Adams. A. testa ovali, ventri- 
cosa, alba, nitida, semipellucida, transversim striata, dorso obscure 
angulato ; apertura angusta, canalibus brevibus, obtusis, integris, 
labio postice vir calloso, antice excavato, labro complanato, lirato, 
intus denticulato. 
Hab. New Caledonia. Mus. Cuming. 
This is a pure white, pearl-like shell, semi-pellucid, finely striated 
across, gibbous on the back, with hardly any trace of the usual callus 
at the hind part of the inner lip, and with a prominent longitudinal 
ridge at the fore part. 
3. Ampuiperas RHOoDIA, A. Adams. (Pl. XXVIII., fig. 8.) 
A, testa ventricosa, subpyriformi, rosacea, albo-varicosa, dorso 
