NOTES AND MEMORANDA, 65 
On reinserting the body thus arranged, and illuminating 
the crystal on the stage with convergent light by means of a 
condenser, the rings and brushes could be perfectly seen. 
The whole double series of rings on a biaxial crystal of car- 
bonate of lead was thus shown. 
The condenser used was a “ kettle-drum” of two plano- 
convex lenses. The objective on the nozzle of the micro- 
scope was a two thirds of Ross; that within the draw-tube 
a three-inch objective of the same maker.— Philosophical 
Magazine. aN 
Globigerina O0oze.—F rom the Cape, as far south as our sta- 
tion in lat. 46° 16’, the Challenger found no depth greater than 
1900 fathoms, and the bottom was in every case “‘ Globigerina 
ooze ;’’ that is to say, it consisted of little else than the shells 
of Globigerina, whole, or more or less broken up, with ve 
small proportion of the shells of Pulvinulina and of Orbulina, 
and the spines and tests of radiolarians and fragments of the 
spicules of sponges. : 
Mr. Murray has been paying the closest attention since the 
time of our departure to the question of the origin of this 
calcareous formation, which is of so great interest and im- 
portance on account of its anomalous character and _ its 
enormous extension. Very early in the voyage he formed the 
opinion that all the organisms entering into its composition at 
the bottom are dead, and that all of them live abundantly at 
the surface and at intermediate depths over the Globigerina 
ooze area, the ooze being formed by the subsiding of these 
shells to the bottom after death. 
This is by no means a new view. It was advocated by the 
late Prof. Bailey, of West Point, shortly after the discovery, 
by means of Lieut. Broke’s ingenious sounding instrument, 
that such a formation had a wide extension in the Atlantic. 
Johannes Miller, Count Pourtales, Krohn, and Max-Schultze, 
observed Globigerina and Orbulina living on the surface ; 
and Ernst Haeckel, in his important work upon the Radiolaria, 
remarks that “ we often find upon, and carried along by the 
floating pieces of seaweed which are so frequently met with 
in all seas, foraminifera as well as other animal forms which 
habitually live at the bottom. However, setting aside these 
accidental instances, certain foraminifera, particularly in their 
younger stages, occur in some localities so constantly and in 
such numbers, floating on the surface of the sea, that the 
suspicion seems justifiable that they possess, at all events, at 
a certain period of their existence, a pelagic mode of life, 
differing in this respect from most of the remainder of their 
class. ‘Thus Muller often found in the contents of the sur- 
VOL, XV.—NEW SER, E 
