17 
upon as more than the mere result of a coalescence of the 
bases of the Pseudopodia. Orbulina uni versa and Globi- 
gerina bulloides are two forms found in great abundance 
in this Dogs Bay sand ; they are interesting as being the 
prevailing shells in deep-sea dredgings and also as always 
occurring together, a fact Avhich has been noticed by Pro- 
fessor Williamson, who has long entertained the belief that 
there is some very close relationship between them. The 
Orbulinse are found of very different sizes, the largest 
being as much as six times the diameter of the smallest, 
with every possible intermediate gradation ; and considering 
that the shell can only be made of the exact size of the body 
on which it is moulded, while that body will continue to 
arow, he could not avoid the conclusion that in this case 
at least, as often as a larger shell is required, the animal 
must withdraw itself entirely from the old one and cast it off. 
But a consequence of this view that the single-chambered 
Foraminifera cast their shells at intervals to form new ones 
is that they will occasionally be freed for certain periods from 
the restraint of the shell, and be in a condition to effect that 
spontaneous division which is so striking a feature in the 
Rhizopoda. 
There are other specimens of Orbulina found occasion- 
ally in the Dogs Bay sand which have a very special 
interest, since they appear to show most clearly that Globi- 
gerina is merely a younger state of this species, — a fact 
which was first announced by Mr. L. F. Pourtales, (Ann. 
and Mag. Nat. Hist. 1858), illustrated by specimens ob- 
tained from dredgings in the Gulf Stream. Dr. Carpenter 
mentions the observations but expresses doubt as to their 
correctness. The Dogs Bay specimens however seem to 
corroborate them most fully, for they show the perfect 
Globigerina inside the sphere of the Orbulina. 
