4 
Mr. W. C. Williamson on the Recent 
nuteness of the species composing it presents a great obstacle to 
an accurate examination.^^ 
The more recent writers have followed in the steps of those 
who preceded them, with two exceptions. 
Professor MacGillivray, in his work on the ' Molluscous Ani- 
mals of Scotland/ &c., made the first attempt to classify the Bri- 
tish Poraminifera according to the comprehensive system of 
D^Orbigny, and at the same time reunited the Lagence to those 
organisms from which D^Orhigny had separated them. 
In 1839 Ehrenberg laid before the Academy of Sciences at 
Berlin the brilliant results of his investigations into the structure 
and relations of the Poraminifera. He completely exploded the 
long-received opinion that they were Cephalopoda, and proved 
beyond doubt that they were zoophytic, being in fact Bryozoa 
allied to Flustra, Eschar a, Cellepora, &c. In his classification of 
the Bryozoa according to his new views, of which a copy was 
published in the ^Annals and Magazine of Natural History^ 
for 1841, vol. vii. p. 302, he places some of the Lagence at the 
head of the list of Poraminifera, under the name Miliola ; ap- 
parently considering them the most simple and rudimentary form 
of that curious group. This is I believe the last published notice 
of the genus, except what is to be found in Thorpe^s ^British 
Marine Conchology^ (which contains no more than had been 
previously given by Hr. Pleming and other conchologists), and a 
few remarks in the memoir before alluded to on the microscopic 
character of the Levant mud. 
On subjecting the Lagence from the Boston and March deposits 
to a close examination, and especially by adopting Ehrenberg^s 
plan of mounting them in Canada balsam and viewing them as 
transparent objects by means of transmitted light, I soon ob- 
served some interesting facts which had apparently escaped the 
notice of our British conchologists. One of the first w^as, that 
these objects, the whole of wdiich consist invariably of one iso- 
lated cell or chamber, require, nevertheless, to be divided into tw o 
distinct groups or genera; the one characterized by a long ex- 
ternal neck or tube, wdth a small patulous orifice at the free ex- 
tremity, projecting from the upper part of the cell (see PI. I. figs. 
1, 6, 9 & 10.) ; whilst in the other there exists a very similar tube, 
only occupying a reversed position. Instead of projecting exter- 
nally, it descends into the internal cavity', still taking its rise 
from the upper portion of the cell, towards the low^er part of the 
interior of which, the patulous orifice of the tube presents itself 
when it attains its full length (see Plate II. figs. 14, 16 & 22). 
A little time after making this discovery, I received from Hr. 
Bailey of New York, specimens of Lagena striata (wEich is one 
of those having an external tube), and attached to it was the 
