10 SHALLOW-WATER FORAMINIFERA OF TORTUGAS REGION. 
COLOR IN LIVING SPECIMENS. 
Most of the Miliolide, unless incrusted with colored sand-grains, 
have little color in dried tests. In the living state, however, there 
is often much color, due to different causes. In the Quinqueloculine 
group there is often a beautiful light-pink color in live specimens, 
due to the color of the protoplasm, as may be seen in that projecting 
from the aperture. This is often sufficient to color the whole test, 
especially with transmitted light. 
In Orbitolites duplex there is usually a salmon-color in living 
specimens which do not have commensal alge. The outer one or 
two annuli usually are filled with nearly colorless protoplasm. 
Often the general color is due to alge, as will be noted later. 
In the Rotaliide there is often a reddish-brown color, in the 
earlier chambers at least. Instead of being caused by the protoplasm 
alone, it seems in some species at least (see Tretomphalus bulloides, 
p. 42) to be due to a thin lining of colored material which is distinct 
from the calcareous wall of the test. In Truncatulina rosea there is 
developed a peculiar rose-red color which persists and colors nearly 
the whole test. A bright red color is also characteristic of 
Homotrema, which is abundant in the reefs. In the Globigerinide, 
especially in Globigerina rubra, there is again a distinctly rose color, 
especially in the early chambers. 
Found with the Homotrema is a small crab with reddish spots of 
the same color as the Homotrema, the remainder of the carapace and 
legs of the color of the dead coral. The resemblance is very striking. 
COMMENSAL ALGAE. 
The association of unicellular alge with certain of the Foraminifera 
has been known for some time. There is evidently a commensal 
relation between the two, although the exact interrelations have not 
been definitely made out. In Jridia diaphana there are often great 
numbers of a small unicellular alga, somewhat fusiform in shape, of 
a brownish color, and about 0.006 to 0.007 mm. in length. These 
are usually associated with the pseudopodia in Jridia. When the 
pseudopodia are extended and active, nearly all the alge are outside 
the actual test, and when quiescent they are apparently stored in 
the area at the peripheral portion of the central mass and in the 
radial canals. 
In Orbitolites duplex there are bodies in the test, usually in the 
more central portions. These are brownish and completely pack 
the chambers, irregularly rounded and about 0.006 mm. in diameter. 
These are very different from the alge noted in Jridia. 
In the Philippine collections, green alge were noted in great 
abundance in Orbitolites and Cyclolypeus, but no green ones were 
noted at the Tortugas. 
