AXATOITT AXD PHYSIOLOGY OP THE POEAMIHIPEEA. 
177 
■was made upon some fossil specimens preserved in clialk flints. 
Since then fnrtlier indications have been obtained by Scbnltze^ 
Dr. Carpenter^ and Dnjardin_, but especially by tbe last-named 
observer. He found that some Miliolge invested tbeir shells 
■with a brown slimy substance^ in which small granules soon 
made their appearance (flg. 16)^ the latter soon succeeding 
in detaching themselves from the |)arent organism. In two or 
three weeks they developed into youug shelled Miliolge^ which 
shortly afterwards threw out their characteristic pseudopodia 
and crawled about the glass in which they were preserved. 
An examination of the original shell showed that the produc- 
tion of the young brood had been at the cost of the life of the 
parent animal^ the greater part of the sarcode ha-ving resolved 
itself into these granules. These changes coincide so closely 
with similar phenomena occurring in some other Rhizopods_, 
that no doubt need be entertained respecting the accuracy 
of the observation. "Wliether any combinations of sperm and 
germ cells preceded this resolution into granules, indicating 
some higher process than mere budding, is yet unknown. In 
addition to the reproductive process just described, I long ago 
obtained evidence of a multiplication of the .Foraminifera by 
some flssion of the germ into two halves prior to calcification. 
I found several specimens in which calcification had com- 
menced before the fission had been completed. These were 
objects in which the segments were normally arranged in one 
linear series j but in the examples referred to, two such series 
diverged from the primary or germinal segment,* both 
exhibiting the same external aspects and belonging to the 
same variety. We thus obtain indications of at least two 
modes in which the Foraminifera are multiplied. 1st. By 
resolution of the sarcode into reproductive germs ; and 2nd, 
by the fission of these or some similar germs into two parts 
prior to calcification. The circ'amstance that the two halves 
of the twin specimens just spoken of belong to exactly the 
same variety, is sufficient proof that this fissiparous germination 
is not the source of the multiplied varieties which all the 
species of Foraminifera exhibit. Just as in the floricultural 
Vv'orld, fission, or the separation of cuttings, is used to per- 
petuate the same variety, whilst seeds, products of sexual 
reproduction, are used as the source of new varieties ; so in 
all probability it is amongst the Foraminifera. But whether 
the germs noted by Dujardin are those amongst which the 
new varieties spring up, or whether there remains some 
undiscovered mode of sexual reproduction, has yet to be 
ascertained. 
* See Foraminifera of Great Britain, tab. 1, fig. 32 a, and tab. 2, fig. 49. 
VOL. IV. XO. XIV. X 
