164 SIDNEY F. HARMER. 
given in the preliminary note already referred to,—which has 
come into my hands since the above was written. Cuénot 
throws doubt on the value of the evidence given by the reaction 
of the several tissues to pigments such as indigo-carmine in 
elucidating the nature of the excretory processes ; and supposes 
that the absorption of carmine by the pericardial tissue of 
Insects, for instance, is due to the affinity of that tissue for 
colouring matters (see p. 398). The enumeration given by 
Cuénot of the details of the absorption of various pigments by 
certain tissues to which an excretory function is usually not 
ascribed does not seem to me so convincing, in Cuénot’s sense, 
as the demonstration by Kowalevsky and others that these 
pigments are selected by organs known to be excretory in 
nature in the opposite sense. Cuénot shows that the leuco- 
cytes of Polyzoa are quite similar to the “amibocytes” of 
other animals (see p. 407), the most important function of 
which would appear to be the transformation of the peptones 
thrown into the blood by the alimentary canal into non- 
dialysable albuminoids. The same author alludes to the 
formation of “ pseudo-plasmodia” by the ‘‘ amibocytes” of 
various animals (cf. the description given on p. 1831 of a 
similar process in Flustra); and mentions more than once 
the occurrence, in various Invertebrates, of cells whose 
granules exhibit a Brownian movement, and which he usually 
regards as of respiratory nature (“hématies”’). I have not, 
however, found in Cuénot’s figures or text an account of any 
cells which can be exactly compared with the remarkable cells 
above described in Bugula avicularia (see p. 135). 
