AViLLiAMSON on Faujasina. 
91 
occupying the intra-septa] and central passages, should have been 
the minute pseudopodian foramina. The structure is so very 
different in this respect, from anything that has been previously 
observed, that I am afraid to speak with too much certainty on 
the subject, though I entertain but little doubt respecting it. 
On examining the external contours of young examples of 
this species, we often find the apex occupied by a deep and 
irregular depression, surrounded by the projecting upper 
extremities of the segments constituting the external convolu- 
tion. This depression, which is really identical with the 
irregular central cavity (fig. 5 g^g\ subsequently becomes 
arched over by a calcareous layer (fig. 1 d\ derived from the 
upper portions of the newer convolutions. The roof thus 
formed is perforated by large apertures (fig. 6 ^), through 
which a free communication is maintained between the 
external medium and the enclosed space. The nature of the 
latter varies considerably. Sometimes it exists in the form of 
a large irregular cavity, as already described, and at others as 
an intricate network of large canals. The character of the 
external orifices also varies. In some examples they are large 
and patent, as in fig. 6 ^ ; in others, numerous smaller tubes, 
ascending from the subjacent network, converge at some super- 
ficial depressions which occupy the position of the larger 
orifices. Fig. 6 represents a thin superficial section made in 
the plane of the oblique sides of the conical shell and exhibits 
three septa (6 c), with the large orifices of their intra-septal 
canals (hf \ part of the external parietes of four segments 
(6 d\ densely perforated with minute pseudopodian foramina, 
part of the inferior peripheral margin (6 e), and a small lateral 
portion of the dome-like apex of the shell (6 a). 
The preceding facts are sufficient to show that the subject 
of this brief memoir presents a very different structure from 
any of the Foraminifera hitherto described. Whether or not 
my supposition as to the probable occupation of the intra- 
septal canals and spaces by the gelatinous soft animal be 
established, it is obvious that this organism supports the con- 
clusion at which I arrived in a preceding memoir, viz. that the 
soft animal had the power of extending itself externally far 
beyond the limits of any individual segment, and would thus 
be able to secrete calcareous matter in other situations than the 
mere parietes of its own segment. It is only in this way that 
we can explain the production of the dome-like covering which 
encloses the central umbilical cavities and their ramifying 
canals. But if it should be ultimately proved that the soft 
tissues have occupied all these irregular cavities, we shall then 
have a form of organization which, from its great variability 
