EEPOET ON THE FOEAMINIFEEA. 
347 
wall contain a certain amount of siliceous or calcareous sand, and the same condition has 
been observed by Carter in the earlier stages of the shell. 
With respect to the general structure of the test, Mr. Carter has pointed out the 
“resemblance that exists between the spicular bodies and the scales of Euglypha alveolata, 
&c., among the fresh-water Ehizopoda, inasmuch as the ‘ scale/ like the spicular body, is 
formed by the animal itself, and subsequently cemented together by chitinous substance 
to form the test — thus differing from the tests of other Ehizopoda (where the particles 
are foreign and all of the same size) in being proportioned in size to that of the chamber 
which they respectively cover.” The last clause of this quotation refers to the smaller 
size of the spicules in the earlier portions of the test. It may just be added that the 
cement appears to be in part at least calcareous. 
The student of the Foraminifera accustomed to the spicular tests of Marsipella, 
Haliphysema, and Pilulina, will naturally ask how far it can be demonstrated that the 
spicules of Carterina are secreted by the animal itself, and are not extraneous bodies, 
selected as building material, in the same way as siliceous spicules are employed by the 
aforesaid genera. The following considerations bear upon this point : — there is no 
admixture of different sorts of spicules, as in the cases referred to, but they are all of the 
same form and character ; there are no broken spicules, such as invariably exist in large 
proportion in the composite tests of other genera ; in each test spicules are found in 
different stages of growth, and in the investment of the smaller chambers the spicules 
are of correspondingly smaller size ; specimens of the organism obtained from areas very 
far apart, and under different external conditions, have spicules identical in size, shape, 
and composition ; other arenaceous Foraminifera from the same localities have no spicula 
of similar character ; and lastly, in no specimen of Carterina has any spicule been 
identified as pertaining to any particular species of sponge. 
In connection with this subject, attention may be drawn to an interesting organism 
described by Mereschkowsky , 1 under the name Wagnerella borealis, and treated by him 
as a Sponge nearly allied to the Physemaria of Haeckel. In form and habit it resembles 
Haliphysema ; and, in addition to the brush of spicules at the distal extremity, the 
chitinous peduncle has embedded in it numerous calcareous bodies of the same general 
character as the spicules of Carterina. Since the foraminiferal affinity of Haliphysema 
has been established, and the existence of calcareous spicula in the test of a well-defined 
type of Foraminifera has also been demonstrated, it would be interesting to know more 
of the actual structure of an animal, which, to judge by its investment, appears more or 
less related to both. 
Of the distribution of Carterina spiculotesta little is known beyond the fact that it has 
been found attached to pieces of coral, nullipore, and the like, from the comparatively 
shallow water of tropical and subtropical seas. Mr. Carter’s original specimen was from 
1 Ann. and Mac/. Nat. Hist., 1878, ser. 5, vol. i. p. 70, pi. vi. 
