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SUMMARY OF CURRENT RESEARCHES RELATING TO 
Gland of Auricle in Paludina, and Nephridial Gland in Murex.* — 
M. L. Cuenot describes the wall of the auricle of Paludina vivipara as 
being considerably thickened. It is covered externally by a cubical 
epithelium, below which is a thick muscular and connective zone, which is 
crowded with nuclei ; on its inner side this zone is in direct contact with 
the blood. On teasing the wall, after treatment with osmic acid, picro- 
carmine and glycerin, the nuclei of the stroma may be seen in the course 
of being transformed into amoebocytes. A considerable number of them 
are surrounded by the refractive granules characteristic of mature 
amoebocytes, and are ready to pass into the cavity of the auricle ; it is 
quite obvious that we have to do here with a lymphatic gland. Fixation 
with Flemming’s liquid shows the same facts even more distinctly. The 
author has already described another lymphatic gland in P. vivipara , 
which is situated in the gills. The products of these two glands are 
identical, and the two organs are simultaneously functional. 
The nephridial gland of Murex brandaris, teased as before, is found 
to have its glandular tissue formed of a plexus of fibres, crowded with 
nuclei and cells. The former do not develope into amoebocytes, but 
take, on their death, the place of certain cells. These cells, of which 
there is a large number, are very large (10 /x to 25 /a), ovoid or 
spherical in form, and are bounded by a very distinct fine membrane. 
They inclose a central nucleus ; the cellular cavity is filled with large 
refractive granules, which are yellowish-green during life and proteid 
in composition. When alive they actively absorb fucbsin, and become 
red ; they are coloured grey by osmic acid. These cells are not a charac- 
teristic element of the nephridial gland, for they are found wherever 
there is connective tissue, but they are specially abundant in that organ. 
The histological structure of the nephridial gland of Murex brandaris 
leads us to suppose that it is not a lymphatic organ, but merely an organ 
of reserve. 
Mechanism of Respiration in Ampullariidse.f — MM. P. Fischer and 
E. L. Bouvier have had the opportunity of studying the mechanism of 
respiration in Ampullaria insvdarum and Lanistes Bolteniana. The former 
of these was the subject of the observations of Guilding, Cazenavetti, 
and Bavay, and, when in water, exhibits a mode of pulmonary respira- 
tion curiously similar to that of Cetacea. When immersed in water the 
mollusc breathes by its gills. As the siphon divides the left pallial cleft 
into two slightly unequal halves fine granules of carmine maybe seen to 
penetrate into the chamber by the right half of the cleft ; they are 
rapidly directed from before backwards, and from right to left, and the 
water does not seem to take more than six to eight seconds to make the 
entire course of the branchial chamber. When the animal is on land 
the lung plays an essential and exclusive part in respiration ; the pul- 
monary orifice opens and closes alternately, but not with great regularity, 
and these movements correspond to elevations and depressions of the floor 
of the lung. These irregular movements of inspiration and expiration 
are powerfully aided by the general movements of the body. 
While Ampullaria is dextral, Lanistes is sinistral, and the mechanism of 
respiration is altogether different. Lanistes respires air and water by the 
* Comptes Kendus, cx. (1890) pp. 1275 7. f T. c., cxi. (1890) pp. 200-3. 
