PHYSIOLOGY OP LAMELLIBRANCH BLOOD-CORPUSCLES. 607 
Mytilus edulis, Ostrea edulis, Unio pictorum, and 
Anodonta cygnea. Cuenot (2) describes a “ glande 
lympbatique ” at the base of the gills, where the corpuscles 
originate, and recognises coarsely and finely granular cor- 
puscles, and a third variety consisting of a nucleus with very 
little surrounding protoplasm. He considers that these are 
all derived by degenerative changes from the coarsely granular 
form. In the case of Cardium norvegicum I agree with 
Cuenot’s classification, but am inclined to consider that he 
has scarcely published sufficient evidence to warrant the 
statement that the other varieties are degenerated forms of 
the coarsely granular corpuscles. 
The fact that the plasma of Lamellibranch blood does not 
coagulate has long been known, and Geddes (7), in 1879, 
described the plasmodial masses formed by the agglutination 
of the corpuscles in shed blood. Dakin (4), in his monograph 
on Pecten, suggests that these plasmodia may act as plugs by 
which haemorrhage from a wound may be checked, but does 
not enter into the causes which determine this agglutination, 
nor its function in the healing of wounds. 
The question of phagocytosis has not been fully investigated. 
Ray Lankester (11 and 12) first recognised the phagocytic 
action of certain green amoeboid cells which he found on the 
surface of the gills of “green” oysters, and later de Bruyne 
(3) described the way in which certain wandering corpuscles 
invade and destroy the epithelium of the gills, and finally 
escape. De Bruyne attributes an excretory function to these 
cells, and considers the “aqui poriferi,” which were formerly 
supposed to communicate directly between the blood-spaces 
and the surrounding water, to be due to erosions of the 
epithelium caused by the emigration of these cells. In the 
same paper he mentions the ingestion of carmine granules by 
the phagocytes. No account has yet been published of the 
phagocytic action of the corpuscles on bacteria, though, 
owing to the fact that the blood as a whole does not coagu- 
late, many difficulties in the way of such investigations are 
eliminated. 
