144 
POPULAE SCIENCE EEVIEW. 
The Anatomy of Anodonta. — In the Intellectual Observer for September 
we find an important paper on the structure of the swan mussel {Anodonta 
cygnea), by the Rev. W. Houghton, who points out some interesting pecu- 
liarities in the arrangement of the parts composing the so-called crystalline 
style. The latter body is a cylindrical transparent semi-cartilaginoid mass of 
tissue which fills a long coecum that extends from the lower part of the 
stomach through the convolutions of the intestine. This body, which is 
absent in aU uni-muscular bivalves save Anomia, is not confined to Anodonta 
and Unio among dimyaria, as hir. Houghton appears to conclude upon the 
authority of the late M. Moquin-Tandon. It has been found by Siebold 
and others, in Pholas, Solen, Area Mactra, Donax, Cardium, and Tellina. 
Siebold describes the style of Anodonta as being composed of two distinct 
portions, a cortical and medullary. “ The first, which forms a kind of tube, is 
homogeneous, transparent, and formed of concentric layers of the consistence 
of the white of an egg. The second is equally homogeneous and transparent, 
but is of a more gelatinous nature and contains a quantity of small batons 
insoluble in acid, which at the points where most aggregated, give this organ 
a whitish colour when examined by reflected light.” Mr. Houghton’s paper, 
while it does little more in other respects than recapitulate the results of 
other observers, has afforded us some very interesting infonnation regarding 
the microscopic structure of this “ style.” He finds it “ to contain embedded 
within its substance, large numbers of a very minute filiform animalcule, which 
may be seen under the microscope to shoot backwards and forwards in the 
gelatinous mass. I have failed hitherto to make out any structiu-e in these 
curious parasitic vibrioid wonns.” Fact is always valuable, hypothesis is fre- 
quently objectionable, and while we think there is every credit due to Mr. 
Houghton for the important observations he has made, we must certainly say 
it would have been wiser to have reserved judgment concerning the nature of 
the peculiar structures observed. Till further evidence is advanced, therefore, 
we must remain in doubt as to the exact character of Mr. Houghton’s 
“ curious parasitic vibrioid worms.^’ It is strange that neither Poli nor Boja- 
nus should have observed these bodies, but possibly their instruments were 
not sufficiently powerful. The memoir of the latter, which is to be foimd in 
the Isis for 1827, is of a very meagre and unsatisfactory character, and the 
figure of the style (Crystal-Grifiel) represents it as being a talc-fike plate of 
about a quarter of an inch long, of a somewhat triangular outline, and one of 
whose sides is irregularly serrated. 
The Structure of rare Corals. — In a recent number of the Comptes Rendus 
we find a memoir of M. Lacaze-Duthiers, upon the structure of two species 
of Antipathes, A. sub-pinnata, and A. salix. These are, of all species, the 
most difficult to study, and this is why we know so little about them. They 
live at immense depths, and are never taken by the ordinary coral-coUectors. 
They are formed of so delicate a tissue, that the shortest exposure to the air 
causes it to wither and disappear ; and as it is extremely difficult to induce 
the fishermen to place and keep them in sea-wateflf during their trip, the 
study of them becomes no easy matter. In the former of these two species, 
M. Lucaze-Duthiers found only two of the visceral septa, which are so charac- 
teristic of all other corals. 
