CORAL-MAKING ACTINOID POLYPS. 4] 
body; but whether the young Actiniz were produced by bud- 
ding from this part of the body, or whether they had colonized 
there after being produced in the ordinary way, he was un- 
able to determine. In all cases the young ultimately sepa- 
rate from the parent. 
These polyps have also the faculty of reproducing lost 
parts; and to such an extent that a mere fragment, if it be 
from the lower part and include a portion of the base, will re- 
produce all the rest of the Actinia, even to the disk, tentacles 
and stomach. Thus the mere forcible tearing of an Actinia 
from the rock to which it is attached may result in starting a 
crop of new Actiniz. 
Although Actiniz have no internal coral secretions, they 
sometimes make a thickened epidermic plate at the base, and 
also in a few cases around a part of the body. ‘This is how- 
ever not a result simply of an epidermic secretion, but arises 
from an exudation of mucus from the surface, and the entan- 
gling thereby of minute particles of foreign or dead matters. 
A case of the kind, in an Edwardsia where the body is thus 
encased, is mentioned and explained on page 25. 
The above are the more prominent characters of the Actin- 
ia tribe of polyps. The special features distinguishing them 
from the coral-making polyps are the following: (1), They are 
simple animals, or, if they bud, the buds early separate from 
the parent ; (2), They have a muscular base ; (3), They are gen- 
erally capable, more or less perfectly, of locomotion on the base 
by means of its muscles ; (4), They sometimes possess rudimen- 
tary eyes; (5), They have no internal coral secretions. Each 
of these characters is evidence of the superior grade of this di- 
vision of Polyps. 
