60 
Dr. Wallich, on the Polycystina. 
may undoubtedly be said to characterise the primary division, 
it involves the separation of the Foraminifera from the whole 
of the other Rhizopods, and hence, from the Polycystina, the 
animal of which 1 hope to be able to show is identical, in 
every essential respect, with that of the former family. 
Whilst the presence or absence of closely foraminated 
multiple poreuses'^) chambers, even did it afford a distinc- 
tion between the two families, ought no more to be regarded 
as proof of their physiological distinctness from each other, 
than the composition of the test in Gromia (supposing no 
valid ground for such separation to exist, as in reality does 
exist) can be accepted as a sufficient reason for separating 
it from the Foraminifera. 
Again, whilst the greater frequency with which the pseudopo- 
dia inosculate might, at first sight, be regarded as distinguish- 
ing the Gromida from the Amcebiiia, it likewise removes them 
from the Actinophryna, in some of the genera belonging to 
which this property is by no means rare. It will be seen 
hereafter that, although I follow MM. Claparede and Lach- 
mann in placing Gromia apart from the Foraminifera, I do so 
on totally distinct grounds from those named by them, namely, 
in consequence of my having detected in that genus the 
presence both of a nucleus and contractile vesicle. 
With regard to the distinguishing character said to be fur- 
nished by the yellow cellules,^^ I may observe that bodies, 
which I believe to be identical with them in origin and office, 
have been met with by me in all the Rhizopods, whether 
marine and fresh- water. In such of the fresh-water genera 
as have exhibited them the yellow colour is absent. But when 
we take into consideration the fact that tints, varying from 
the most brilliant crimson to shades of olive-brown and 
brilliant yellow, are constantly met with in the sarcode of the 
oceanic forms, and that these tints apparently vary with 
varying conditions of the same species, if not actually of the 
same individual, we may rather look on the colour of the 
so-called cellules as being immaterial, than as affording a 
valid distinguishing feature in their structure. In the 
Foraminifera they have been very generally noticed. In the 
Acanthometrina, Thalassicollina, and Polycystina, they con- 
stantly occur, and also in two new families of which I shall have 
to speak hereafter. But they are present also in the Amcebina 
and Actinophryna, although, as already stated, destitute of 
colour in these genera ; the reason for assuming their identity 
in the latter case with the ''^yellow cellules,^^ being that evi- 
dence exists in both cases to show that, wherever present, these 
bodies constitute the rudiment of the young organism. 
