Sea-bottom procured by H.M.S. ‘Challenger. 289 
shows that the specimen from which it was taken had both its 
chambers and the flask-shaped cavities of the exogenous deposit 
filled with sarcode not distinguishable in any respect from that of 
the floating specimens. From these important observations (which 
had not been made public when the sheet of my ‘ Introduction to 
the Study of the Foraminifera’ comprising the Globigerine family 
passed through the press, but which I have myself subsequently 
confirmed in every particular) it seems an almost inevitable in- 
ference that the subsidence of the Globigerine to the bottom is the 
consequence, not of their death, but of the increasing thickness 
and weight of their shells, produced by living action. As long as 
the number of segments continues to increase, the carbonate of 
lime separated by the sarcodie body from the circumambient water 
goes to form the walls of additional chambers; but when this 
chamber-formation ceases (which usually occurs when the shell 
consists of either 12 or 16 segments), it is applied to thicken 
the walls of the chambers already formed; and from the rapid 
subsidence of the Gilobigerine taken up from the sea-bottom when 
thrown into a jar of sea-water, it seems to me inconceivable that 
they can be floated by their animal inhabitants when once the 
exogenous deposit has attained any considerable thickness. 
That the Globigerine which have subsided to the bottom con- 
tinue to live there, is further indicated by the condition of the 
sarcodic contents of their shells. Im any sample of Globigerina- 
ooze that I have seen brought up by the dredge or the sounding- 
apparatus, part of the shells (presumably those of the surface- 
layer) were filled with a sarcode body corresponding in condition 
with that of Foraminifera known to live on the sea-bed, and 
retaining the characteristic form of the organism after the re- 
moval of the shell by dilute acid. As Dr. Wallich pointed out 
(‘ North-Atlantic Sea-bed, p. 139), the sarcode of these is viscid, 
and inclined to coalesce again when crushed ; the shell has a vivid 
but light burnt-sienna colour ; and sarcodic bosses, like retracted 
pseudopodia, are distinguishable upon its exterior, The only mis- 
giving I ever had in regard to the living condition of the Globi- 
gerine presenting these characters, was caused by the absence of 
any pseudopodial extensions; and this source of doubt has been 
now removed by the statement of Prof. Wyville Thomson, that 
no pseudopodia have ever been observed by Mr. Murray to be put 
forth by the Globigerine captured in surface-waters.—In the same 
sample will be found shells distinguishable from the preceding 
by their dingy look and greyish colour, by the want of consistence 
and viscidity in their sarcode contents, and by the absence of any 
external sarcodic investment; these are presumably dead. Other 
shells, again, are entirely empty; and even when the surface- 
stratum is formed of perfect Globigerine, the character of the 
deposit soon changes as it is traced downwards. ‘The sedi- 
ment,” as was correctly stated by Prof. Wyville Thomson, “ gra- 
dually becomes more compact; and a slight grey colour (due, 
probably, to the decomposing organic matter) becomes more pro- 
