20 NATURAL SCIENCE [JuLy 
parations and tow-net gatherings made during the Challenger Ex- 
pedition, the following species of Foraminifera have been recognised 
as pelagic :— 
Globigerina sacculifera, Brady. Orbulina universa, d’Orbigny. 
as aequilateralis, Brady. Hastiyerina pelagica (d’Orbigny). 
aR conglobata, Brady. | Pullenia obliquiloculata, Parker and Jones. 
5 dubia, Egger. Sphaeroidina dehiscens, Parker and Jones. 
y rubra, d’Orbigny. Candeina nitida, d’Orbigny. 
5 bulloides, d’Orbigny. Cymbalopora (Tretomphalus) bulloides 
4 inflata, d’Orbigny. (d’Orbigny). 
» . digitata, Brady. Pulvinulina menardii (d’Orbigny). 
x ceretacea, d’Orbigny. 7s tumida, Brady. 
dutertrei, Brady. a canariensis (d’Orbigny). 
Af pachyderma (Ehrenberg). F micheliniana (a’Orbigny). 
as marginata (Reuss). 3 crassa (d’Orbigny). 
* Zinnaeana (d’Orbigny). 3 patagonica (d’Orbigny). 
A helicina, d’Orbigny. 
Cymbalopora bulloides! (Fig. 3) can hardly be regarded as a true 
pelagic Foraminifer. It was only captured in the neighbourhood 
of coral reefs, and the curious thing about it is that not a single 
specimen was taken containing ordinary sarcode, similar to that 
observed in the other species of pelagic Foraminifera. In all the 
specimens the shells were filled with immense numbers of minute 
zoospores ; these latter spread over the field of the microscope in a 
cloud-like swarm when a shell was broken under the cover-glass. 
The usual colour of the sarcode of the pelagic Foraminifera is 
yellowish-brown. In Hastigerina it is bright red from the presence 
of red coloured oil-globules and pigment. This red colour enabled 
me to pick up this species with a beaker on the sea-surface more 
easily than other species. In Globigerina bulloides (hirsuta) and 
aequilateralis the yellow-orange colour of the sarcode is due to the 
presence of numerous oval-shaped xanthidiz, or ‘yellow cells, 
similar to tftose found in the Radiolaria. When the sarcode with 
these ‘ yellow cells’ flows out of the foramina, and mounts between 
the numerous spines outside the shell, the whole presents a very 
striking object under the microscope; the transparent sarcode can 
be seen running up and down the long silk-like spines, and the 
‘yellow cells, seated at the base of these spines, quite obscure the 
body of the shell. 
The majority of the species in the above list occur within the 
tropics, and the thick-shelled species occur only in warm water, such 
as Sphaeroidina dehiscens, Pulvinulina menardii (Fig. 4), Pullenia 
obliquiloculata, Globigerina conglobata and sacculifera. The number of 
species becomes less in the temperate regions, Pulvinulina michelini- 
ana and canariensis, Orbulina universa (Fig. 2), Globigerina bulloides 
and imflata being the prevailing forms. In the Arctic and Antarctic 
1See Narr. Chall, Exp., vol. i., pp. 838-9, 1885. 
