26 LIFE AND HER CHILDREN. 
form c, which is called an Orbitolite, has often as 
many as fifteen rings, each with its numerous 
chambers, even when the whole shell is only as 
large as the head of a small pin ; and in ages long 
gone by, the larger Orbitolites had a far greater num- 
ber of rings and thousands of chambers in one single 
shell. The animal builds these in the same way as we 
have seen the Miliolite do it, only after he has made 
one round of chambers with a hole in each, he puts 
out slime-threads at every hole and joins them into a 
ring with swellings in it, like beads upon a string, and 
round these he builds the next row of chambers. So 
he goes on increasing his home till he reaches his full 
size, and then Professor Parker tells us that the slime 
of the outer row often breaks up into myriads of young 
Orbitolites just as the body of the Miliolite did. At 
the same time these forms can also multiply by merely 
breaking in half as the naked Finger-slime does, and if 
by accident a piece of an Orbitolite is broken off it 
can form a new and complete shell of its own. 
If you have now understood how the Orbitolite 
grows, you will see that the only communication it 
has with the outer world is through the minute threads 
which stretch out of the holes of the chambers in the 
last ring (see c, Fig. 4), and that the slime in all the 
middle chambers can get food in no other way than 
by its passing from the outside right through all the 
other rings. This is a tedious way of getting food, 
and we shall find that some of the forms shown in 
Fig. 4 have escaped from it in a most ingenious way. 
These forms (d to k, Fig. 4) have hit upon the plan of 
keeping their thin threads stretched out like the thread- 
slime (a, Fig. i) all the time they are laying down their 
