312 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Mollusca. 
y. Gastropoda. 
Physiology of Pulmonata.* — M. L. Cuenot finds that there are, in 
the Pulmonata, five kinds of excretory cells or organs ; the kidney ; the 
vacuolar and the cyanophilous cells of the liver ; part of the epithelium 
of the excretory canal of the pedal gland (Limacidae) ; and the cells of 
Leydig, which are physiologically similar to the pericardiac glands of 
Lamellibranchs, and the branchial heart of Cephalopods. The first three 
have an acid reaction. The products of digestion are all absorbed 
through the glandular epithelium of the liver. This liver, in Pulmo- 
nates, as in Vertebrates, has the power of stopping all hurtful substances, 
which become fixed in the epithelium, and of which no trace passes into 
the coelom. 
There are two kinds of phagocytes in the Pulmonata ; the cells of 
Leydig absorb and digest the foods, which are of an albuminoid nature, 
while the amoebocytes absorb all strange bodies of whatever kind ; the 
albuminoids are alone digested (in an acid medium), while the other 
substances remain in the connective tissue. 
The cells of Leydig in terrestrial Pulmonates have three functions 
which are performed by one and the same element ; the formation and 
storage of glycogen, excretion, and phagocytosis. The same cells in 
aquatic forms divide the duties, for some are only reserve-cells, while 
others are excretory and phagocytic. 
The blue blood of Pulmonates can only absorb an insignificant 
quantity of oxygen, and the albuminoid contained in it (hasmocyanin) 
has not a respiratory function comparable to that of haemoglobin. The 
amoebocytes of the blood can be reproduced by the direct division of 
pre-existing elements. In the connective tissue there are mucoid cells 
identical with those of Vertebrates. The author is of opinion that the 
calcareous nodules of the connective tissue of aquatic Pulmonates take 
no part in the formation of the shell. 
Pulmonata of Portugal and the Azores-t — Dr. H. Simroth begins 
his memoir with a chapter on Palaearctic Pulmonata rapacia, describing 
Plutonia ( Viquesnelia ) atlantica, Testacella Cuv., Paudeburdia, Glandi- 
nidae, and Trigonochlamys imitatrix Bbttg. He arranges them according 
to their affinities as follows : — I. Glandinidae (the more primitive genera 
now in Central America) ; II. Vitrinoidea ( Plutonia atlantica , native of 
and restricted to the Azores, Vitrina pelagica ) ; III. Hyalinoidea or 
Testacellidea (more developed from east to west ; Daudebardia , Testa- 
cella, Hyalind) ; IV. Limacoidea or Trigonochlamydina ( Pseudomilax , 
Trigonochlamys, Selenochlamys ). 
Proceeding to the Limacidae, Simroth describes Limax maximus L., 
L. variegatus Drap., L. arborum Bouch., Agriolimax agrestis L., A. lum- 
bricoides Morelet, A. immaculatus sp. n., &c. ; Amalia gagates Drap. A 
sketch of the relations and distribution of the Limacidae is then given. 
A third chapter is devoted to Parmacella, a fourth to the Arionidae, 
species of Avion, Geomalacus (6r. Oliveirse sp. n.), Letourneuria, Pro - 
physaon, Ariolimax , Philomycus. The memoir closes with a discussion 
1)1 Arch, de Biol., xiv. (1892) pp. 683-740 (1 pi.). 
t Nova Acta K. Leop.-Car. Akad. Halle, lvi. (1891) pp. 200-423 (10 pis.). 
