560 
DR. CARPENTER’S RESEARCHES ON THE FORAMINIFERA. 
direction. Still their continuity is maintained through all the successive layers of 
which even the thickest part of the shelly disk may be composed. 
106. Besides the radial and vertical systems of canals, there is an annular system, 
which traverses the thick band of shell-substance that usually intervenes between the 
successive annuli, and which is continually brought into view in horizontal sections 
(Plate XXIX. figs. 10, 12). It appears from vertical sections traversing the annular 
septa, that several tiers of these annular canals may exist. I have frequently, traced 
them running continuously for a considerable distance, without appearing eitlier to 
give off any branches, or to communicate with the radial canals; but I have occa- 
sionally seen appearances which indicate that such a communication is established 
by means of canals passing vertically downwards at the angles of the chambers, so 
as to unite the three sets of canals into one continuous system, furnished with a mul- 
titude of orifices upon the surface of the disk. A representation of the whole canal- 
system, as I believe it to exist in this organism, is given in Plate XXX. fig. 4. 
107 . The uses of this canal-system can only be a matter of speculation. Not having- 
had the opportunity of examining specimens in which the soft animal substance had 
been preserved, I am unable to affirm whether the interseptal canals of Cycloclypeus 
are occupied in the living state by a portion of the sarcode-body, or whether they are 
empty ; but as I have unquestionable evidence that the former is the case in Poly- 
stomella, I should think there can be little doubt that it is also true of this genus. 
Now if we come to examine the purpose of this canal-system, we are at once struck 
with the fact, that it can scarcely be requisite for the nutrition of the segments of the 
sarcode-body enclosed within the chambers; since the mutual communication which 
these segments have with each other, seems fully as adequate for the purpose in 
Cycloclypeus, as it is in Orhitolites, Orhiculina, ov Alveolina. If we examine wherein 
this organism so differs from the foregoing as to require such an additional system, 
we may find a not improbable answer in the possession of that additional skeleton 
which intervenes between the proper walls of the chambers ; for the canal-system, 
excavated in the very substance of this, would seem to furnish the appropriate chan- 
nel for its nutrition. And that such is its object, will be shown in a future memoir 
to be almost certainly proved, by the comparison of facts then to be adduced from 
the structure of other genera. 
108. Monstrosities. — Although the number of specimens of this type which I have 
had the opportunity of examining is but small, yet two among them exhibited the 
same kind of monstrosity as that which is common in Orhitolites ; namely, the super- 
position of a vertical plate upon the horizontal disk (Plate XXX. fig. 3). And in each 
it is sufficiently apparent that this plate has originated from the central cell, and that 
its increase has taken place pari passu with that of the horizontal disk. 
109. General Summary. — If, now, we review the principal facts relating to the 
structure of Cycloclypeus, and compare them with those furnished by Orhitolites on 
the one hand and by Nummulites on the other, we shall see that, notwithstanding 
