132 THE MOSS-ANIMALS, 
ganization, consisting either of a single cell, or of larger 
cells containing many others, the cycle of whose lives is 
passed within the polyzoén, feeding upon its juices. These 
indicate the passage of a common stream up the branches, — 
and a return current along the free side, which flows into 
each tube. 
Our Polyzoén, also, has no breathing organs, neither 
lungs or gills to bring the blood in contact with the air, 
of which element there is always more or less in water, 
serving there as upon land, for the respiration of animals. 
The tentacles are supposed to be more especially devoted 
to this purpose, and the water admitted to the interior 
must necessarily purify the blood by the air it brings in, 
but nothing more definite is now known with rogard to 
this function. 
The Moss-animals have two modes of reproduction, 
one by buds, the other by eggs. The former occurs in 
two ways, by free buds or statoblasts, and by eprori 
buds, which develop only in summer. : 
The statoblasts are destined to carry their burdens of : 
vitality safely through the hardships of winter, and to per- ` 
petuate the race by founding new colonies in the spring- 
They appear at first in the shape of bead-like swellings 
from the centre of an organie cord, which connects the 
stomach with the cell (plate 3, fig. 4, and plate 4, fig. 1), _ 
‘passing g between the bases of the muscles,-which retract — 
ie tube. They begin as single cells, but these goof 
ite into two, then into four, and so on, indet- 
