THE ANNALS 
AND 
MAGAZINE OF NATURAL HISTORY. 
[SECOND SERIES.] 
No. 27. MARCH 1850. 
XVI.—On the recent Foraminifera. 
By Wiiiiam Crark, Esq. 
To the Editors of the Annals of Natural History. 
GENTLEMEN, Norfolk Crescent, Bath, Dec. 1, 1849. 
THERE appeared in the ‘ Annals’ for May 1849, a paper of mine 
on the recent Foraminifera, containing some new facts and hy- 
potheses on the anatomical structure of these polypi; a further 
examination during the summer months of this year has enabled 
me to confirm the facts I have already made known, to add much 
new matter, and to afford such rectifications of the hypothetical 
inductions as will stamp them with their proper value. I per- 
sist in my view, that all the calcareous organisms styled Fora- 
minifera are fixtures for life, as is the case with every other 
polyparium of the calcareous division. I considered the speci- 
mens alluded to in my first paper decidedly recent, but the pos- 
session of others which were undoubtedly alive an hour before I 
received them, has convinced me of my mistake. The first spe- 
cimens of Dentalina linearis and Marginulina legumen exhibited. 
in the same shell one half hyaline, and the other with the am- 
mal remains, from which I concluded that the polypi inhabited 
only the two or three anterior cells, and the posterior ones were 
rendered hyaline by the withdrawal of their contents, either by 
absorption or desiccation ; but it is more probable that the entire 
shells so often met with, having all their chambers perfectly 
hyaline, have been cleared out, at least in those species that have 
decided visible apertures, by very minute parasites, and that 
where the chambers are partially emptied the enemy has died 
before its work was accomplished, in consequence of the orifice 
being closed up by agglutinated fine grains of sand. I confi- 
dently rely on this explanation, as in long and careful examina- 
tions of the Miliolide, I have found in them so many variously 
Ann. & Mag. N. Hist. Ser.2. Vol. v. 11 
