ON WANDERING CELLS IN ECHINODERMS, 99 
Ruffer (54, p. 108) notes that some emigrated leucocytes actually 
contain more or less digested microbes which have wandered 
out. Attention has been already called to the question of the 
presence of dust particles in the dog’s tonsil, which must be 
regarded to be still somewhat open, though naturally we must 
rely on the more recent observations, carried on with more 
perfect methods than were those of the older observers. 
These references show that there is considerable evidence 
that wander-cells are of service in getting rid of effete products ; 
in view of them we may return to the Echinoderms. 
MacMunn (12) has shown spectroscopically the presence of 
respiratory pigment in Strongylocentrotus lividus: and 
from his description it seems probable that this pigment, which 
he terms echinochrome,' is that readily soluble, bright- 
coloured (brun d’acajou) pigment which is located in a form of 
ameeboid cell mentioned and described by many authors. What 
relation this or some closely allied pigment has to the pigment 
carried to the exterior (e. g. as 18 above described in Spatangus) 
is not quite clear. The granules are much smaller and of uni- 
form size in the former ; in the case of Echinus sphera the 
spheruliferous cells excreted and those (cellules miriformes) 
of the tissues are, as has already been pointed out, very similar 
in the size of the spherules they contain as well as in their 
actual size, the only difference lying in the colour of the 
spherules. In the fresh dorsal organ I have occasionally seen 
cells containing both clear and dingy spherules, which are 
probably what some authors have described as intermediate 
forms. Prouho (11) considers that there is a close relation 
between the “cellule miriforme” and the pigment (p. 300) 
*‘ sranulations brunatres, spheeroidales, de différents grosseurs, 
tantdt éparses, tantét agglomérées” which occur in Dorocidaris. 
He says, “Ces spherules proviennent probablement des 
globules miriformes qui absorbent peu a peu les matiéres 
excretées par les tissus dans lesquels ils séjournent et finissent: 
1 Cuénot describes a yellow pigment which he calls “ hemoxanthin,” and 
which he asserts without experimental evidence to be non-respiratory (38, 
p. 49). 
