8 MR. F. CHAPMAN ON FORAMINIFERA 
Mr. Carter, who drew attention to the porous nature of the shell- 
wall in this and some other Rhizopods.* 
With regard to the porosity of the shell-wall, it appears to me 
that Carter conclusively demonstrated the presence of pores in 
the wallof the test, and although these pores are not regular 
enough to be denominated tubules, yet they probably serve the 
same purpose for the sarcodic body. Dr. Brady has suggested 
that the puncta on the internal surface of Bdelloidina may be 
only superficial depressions. In corroboration of Carter’s 
original idea, it is worth noting a precisely similar structure in 
the shell-wall of the allied genus Haddonia, in which the test is 
stronger and more inflated, and the structure of the shell-wall 
greatly emphasized. There the porosity of the shell-wall seems 
to exist beyond question. 
The apertural pores at the distal end in Bdelloidina are evi- 
dently the terminations of the labyrinthular canals seen in the 
interior of the shell. 
The width of the test is usually 4 inch (about 4 mm.) and the 
Jength slightly more. One example from Fuafatu, however, 
measures as much as 3 inch (12°5 mm.). 
Bdelloidina is a genus likely to be overlooked, since its habit 
is to seek shelter in hollows of shells and coral-rock, creeping 
over the interior and filling up irregularities in the surface. Its 
usual colour, moreover, is that of a calcareous sand, for it is 
composed of little granules (fragments of organisms) or even 
minute shells, together with occasional sponge-spicules. This fact 
probably explains its rarity in records of foraminiferal faunas 
from coral areas. 
The only localized specimens of Bdelloidina aggregata previ- 
ously obtained were from the ‘ Challenger’ dredgings in shallow 
water near the Admiralty Islands on the north coast of Papua, 
generally adherent to molluscan shells. 
A fossil specimen has been recorded as adherent to a Creta- 
ceous Ammonite from Mr. Matthew Wright’s cabinet fT ; a drawing 
of this was made many years ago which is in the possession of 
Prof. Rupert Jones. I am enabled by the kindness of Prof. 
Jones to give a reproduction of this drawing for the first time. 
(See fig. 1, p. 9.) 
In the neighbourhood of Funafuti Bdelloidina aggregata is 
notably restricted to shallow water. 
* Carter, op. cit. pp. 202-208. 
+ See Brady, Rep. Chall. 1884, vol. ix. p. 320. 
