THE FORAMINIFERA. 61 
and the number and disposition of their chambers, to group them 
into families. D’Orbigny’s classification is good, and deserves to be 
generally adopted, although his names are not so euphonious as 
they might be. This clever naturalist, who ought to be regarded 
as the great historian of this minute people, divides them into five 
families which contain about sixty species :—Shells of a single 
STICHOSTEGA, 
chamber, and those superimposed linearly on a straight or curved 
axis (Stichostega) ; those composed of alternate chambers (£7al- 
lostega); those which have chambers on a common axis, each 
investing half the circumference (A gathistega). In another family 
the chambers are arranged in spirals (/elixostega). 
In this case either the folds of the spiral wind round each other 
ENALLOSTEGA, AGATHISTEGA. 
like a coiled rope, or rise above each other in a corkscrew fashion. 
In certain species the chambers are subdivided by partitions, so that 
a section of the shell shows a kind of trellis work, as in the £z7Zo- 
mostega. Nhat geometry, what mechanism, what harmony, in the 
very meanest of organised beings! The resemblance which these 
little shells bear to those of the nautilus at first led naturalists to 
believe that the animals themselves were of the same species, and 
therefore place the foraminifera with the molluscous cephalopods. 
