14 ZOOPHYTES. 
manner as externally, and for like reasons, as the external waters have 
free admission. 
II]. Gemmiparovs.—l. By single buds, developing young, which 
afterwards become free and independent animals. 
2. By buds, which become developed and remain persistent,—and 
these may be either lateral or terminal. 
Ill. By ArtiriciaL SECTIONS. 
This mode may depend on the same cause as the general distribu- 
tion of the dudding function, and may be properly an analogous pro- 
cess, — both depending on the imperfect character of the nervous 
system, or its absence. 
These modes of reproduction, as they are presented by the diffe- 
rent tribes of zoophytes, will be farther explained in the following 
pages. 
8. Compound Zoophytes. It has been stated that zoophytes are 
either simple or compound, the simple being a solitary animal, with a 
single mouth and its visceral cavity; the compound, a cluster, present- 
ing aS many mouths externally as there are polyps combined, and 
within, as many visceral cavities. ‘This compound structure proceeds 
from the capability, above explained, of increasing by buds; for every 
coral, however large and numerous the colony, commenced from a 
single polyp. In some species the bud grows out as a distinct 
branch from the side of the parent, and branch is thus added to 
branch by successive buddings from the forming polyps. In other 
cases, the young continues attached by one side to the parent, instead 
of forming a prominent shoot, and only their upper extremities appear 
separate. Large zoophytes are thus formed, consisting of myriads of 
polyps united to one another by the tissues that surround the visceral 
cavity of each. 
The several polyps in a compound zoophyte eat and digest sepa- 
rately, and generally carry on as individuals the processes of repro- 
duction and aération; yet all aid in the growth of the common 
mass, though each contributes more especially to its own nutriment 
and the part immediately adjoining. Although their visceral cavi- 
ties are distinct, there are numerous communications between those 
of adjoining polyps, and the fluids may pass more or less freely 
from one to the other. An injury to one part of a zoophyte is felt by 
the polyps some distance around, but not always through the whole 
mass. On pressing the tip of a branch of a large Aleyonium, in 
the Feejees, there was an immediate contraction of every polyp 
