9 
British species of the genus Lagena. 
the presence of pseudopodia, renders it probable that the animal 
of all the Lagence will eventually be found to be like that of other 
Foraminifera, viz. a gelatinous substance capable of projecting 
minute filaments, used probably as organs of progression, and 
also of receiving foreign bodies into its interior by means of the 
tubular orifice, by which substances it is nourished. Whether in 
any species the orifice at the extremity of the tube be furnished 
with a ciliobrachiate polype like that of the Eschara or not, is 
doubtful. The peculiarity in the structure of the membranous 
part of the cell, resembling that of Eschara and differing from the 
Rotalince, would indicate the possibility of some resemblance in 
this point, but my observations on Lagena marginata render it 
scarcely probable. 
The existence of the internal tube of the Entosolenice, though 
so different from what generally occurs amongst the Foramini- 
fera (in which all siphuncular appendages usually project ante- 
riorly and not retrally, as has been already observed by M. Ehren- 
berg), constitutes no real difficulty in the way of classing them 
together; since in an elegant species of Polymorphina, not un- 
common in the Boston deposit, and sometimes occurring on our 
own coast, the outermost cell is furnished with a precisely simi- 
lar internal prolongation of the terminal oral ? orifice, and which 
I have not hitherto seen noticed by any observer. 
As regards the mode of growth of the Lagence one thing is 
certain, viz. that in the young state the cell is very thin, vitreous 
and transparent, whilst it becomes more and more opake with 
age. Here again we have another resemblance to Eschara, in 
which the gemmule after fixing itself to some object first covers 
itself with a very thin calcareous case, which it gradually thick- 
ens by the addition of calcareous particles. In L. striata the 
young cells, which are comparatively small, are perfectly trans- 
parent, whilst the large specimens commonly found in the cabi- 
nets of collectors are strong and quite opake* excepting along the 
costse. From an examination of an immense number of speci- 
mens, it soon became evident to me that the animal must have 
possessed the power of enlarging and thickening its cell with in- 
creasing age. This fact first led me to suspect that in its struc- 
ture it would approach nearer to Eschara than to Rosalina ; an 
induction which subsequent investigation confirmed. Owing to 
its form, the cell could not have been so enlarged if it had been 
merely a calcareous secretion from an internal membrane. It is 
only in young specimens of the true Lagence that the long ex- 
ternal neck is found perfect. On older specimens it is almost 
always worn off : this is especially the case with L. striata. 
* In some instances this opacity arises from the deposition of calcareous 
matter, in others from a thickening of the membrane. 
