8 
Mr. W. C. Williamson on the Recent 
lour, becoming of a paler hue as we approach the larger cells ; 
the terminal ones being almost colourless. In Rotalina Beccarii 
this difference is scarcely to be observed, all the cells being nearly 
transparent ; and in Polystomella crispa, the animal portions fill- 
ing the innermost and outermost cells appear to exhibit no dif- 
ferences of transpareney or colour. A slight deepening of the 
colour is observable in the young cells of Quinqueloculina semi- 
nulum. 
It is from Rosalina globularis that the best specimens of the 
decalcified animal membrane are to be obtained, and from Rota- 
lina Beccarii the next; these two, especially the former, pre- 
serving their contour the best, owing to the greater density of 
the lining membrane. In Polystomella crispa, and in the Quin- 
queloculina, this membrane is so exceedingly thin, and the con- 
tained animal matter in such a thoroughly fluid state, that less of 
a definite form is left on drying the decalcified animal than would 
result from submitting Paramecium aurelia^ or many others of the 
Polygastric Infusoria, to a similar process, corroborating M. Du- 
jardin^s observations, though not the inferences which he deduced 
from them. 
On treating various species of Lagena with dilute nitric acid, 
in the same way that I had done the other Poraminifera, the re- 
sults were of a precisely opposite character to those I had pre- 
viously arrived at, but analogous to those obtained by Milne 
Edwards in operating upon Eschara. I found a strong animal 
membrane, which, had the organism not been dried, would evi- 
dently have been flexible ; not lining the cavity of the cell, but 
retaining all its external form. This was obtained most easily 
from L. Icevis, var. Amphora (fig. 3), and L. striata (fig. 5), in old 
specimens of which the decalcified membrane was of considerable 
thickness. In L. striata the membrane was very thin and trans- 
parent along the costse, but in old specimens thick and opake in 
the intervening spaces, the latter portions being easily separated 
in the form of long shreds. The same transparency in the mem- 
brane was observable in the translucent reticulations separating 
the areolse of Entosolenia squamosa, the areolje being opake. 
The only species which I have hitherto had the opportunity of 
examining in a fresh state is the Lagena (Entosolenia) marginata, 
which was rather abundant amongst the branches of an Anten- 
nularia, which Mr. Jeffreys sent to me from Falmouth, whilst still 
moistened with sea-water. In these specimens, no trace of organi- 
sation was observable in the soft animal ; each cell being filled 
with a perfectly transparent gelatinous fluid, like that contained 
in the outermost cell of a Rotalina, but even still more completely 
colourless. 
The existence of foramina in many of the species, implying 
