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being so, it is composed of three perfectly distinct layers, possibly of four 
strata even. The first, the epidermic layer, is homogeneous, thin, transpa- 
rent, and is composed of cells of a slightly yellow colour, and of extremely 
small size. It is well characterized by the absence of tricuspid spicules, and 
especially by the presence of irregularly-oval or circular vacuoles, more or less 
numerous, and which play the part of stomata, probably facilitating the 
absorption of nutritive liquids by the sarcosome. The second, or medium 
layer, is sensibly thicker than the former. It is formed of yellow cells, 
arranged so as to have a number of irregularly-traced spaces, which look like 
canals hollowed out of the substance of the layer. It is further characterized 
by the presence of star-shaped bodies, sparingly distributed, and of three- 
pointed spicules. The third, which is the deepest layer, is delicate in sub- 
stance, and very difficult to prepare for examination. It is homogeneous ; 
formed of cells (?). It is devoid of stomata. M. Grave thinks that the 
fourth layer is placed between the middle and deep layers, but he has not 
yet been able to isolate it and study its minute characters. 
Zoological Section of the French Academy . — The place of correspondent 
in the zoological section, lately held by M. Leon Dufour, has been given to 
M. Van Baneden, the Belgian naturalist. The thirty-five votes were divided 
as follows For Van Beneden thirty-two, for Pictet two, for Vogt one. 
