a Genus of quasiparasitic Mollusks. 825 
a dozen specimens of the shell which he had thus provisionally 
named in the crevices of Madrepores and other stony corals that 
had been collected on the shore of one of the West-India Islands 
for the purpose of being burnt into lime, and had formed part 
of the ballast of a vessel bound to Europe. As the corals had 
lain on the beach for a long time, Chemnitz thought the shells 
might have been terrestrial, and not marine. Mistakes of a 
similar kind have been made by modern conchologists—e. g., 
Hala Priamus. 
M. Hupé, the able and courteous curator of the natural-history 
collections in the Jardin des Plantes (whose knowledge of the 
recent Echinodermata is very extensive), published in the 
‘Revue et Magasin de Zoologie’ for March 1860 a description 
of another species, under the name of Stylifer Orbignyanus. 
While examining a specimen of Cidaris imperialis, Lam., from 
New Holland, he noticed that two of the spies were unusually 
enlarged, tumid, and irregularly spherical; at their base he ob- 
served two small vertical slits, like button-holes, placed opposite 
to each other. A section of these spines showed that in the 
cavity of one was enclosed an adult Stilifer, and in the other, two 
specimens, which were also adult, besides several embryonic shells. 
With respect to the mode by which the Stilifer had thus be- 
come enclosed, M. Hupé was of opinion that the cavities were 
not made by them, but that the interposition of some part of 
the mollusk had prevented its being completely imprisoned in 
the spine during the progress of the growth of the Cidaris, 
which would otherwise have enveloped and smothered the Stili- 
fer. He was kind enough to show me the specimens; and 
they seemed to present an analogous case to that of Stzlifer 
astericola, which I had examined in Mr. Cuming’s collection. 
Lastly, I would cite an excellent monograph by Dr. Fischer, 
which appeared in the ‘Journal de Conchylhiologie’ for April 
last, on the genera Stylifer and Entoconcha (p. 91 &c.). In this 
monograph all the known species of Stilzfer are redescribed, and 
a new one (S. Pauluccie) well described and figured. According 
to Fischer, the Entoconcha mirabilis of J. Miller, found in 
Synapte at Trieste, is probably the fry of some other mollusk. 
At all events, we want more information about it. It is almost 
microscopic. 
But to return to Stilifer. Fischer suspected that it is not a 
true parasite. He says that the discovery by M. Hupé proves 
that, although living like a parasite on the tegumentary system 
of the Echinoderms or their appendages, the Stilifer does not 
feed on their substance, as has been supposed. Its nourish- 
ment comes with the sea-water through the openings of the 
cavity which it occupies: perhaps its proboscis may be pro- 
