ECHINODERMATA. 
277 
Acuity of renewing organs which many of the zoophytes possess, we 
not here enlarge further upon the subject. 
The Crinoidse are not all like the two species which have been 
Scribed. There is an entire family of animals belonging to this 
clas s ; namely, the Comatula, which are fixed in their early days, but 
Se Parate themselves from the rooted stem in their adult age, and, 
throwing off the bonds imposed on their youth, live side by side with 
^‘ e aster ias, with whose company they seem much pleased. The 
termites and the star-fishes thus live in company, and that at 
prodigious depths, and under a body of water which no light can 
le ach. Imagine the existence of animals which pass their lives in 
S ' lc h eternal funereal darkness. The family of Comatula are found in 
seas of both hemispheres. Their bodies are flat — a large calcareous 
Ptate formed like a cuirass upon their backs — presenting, besides, cirri 
Proposed of numerous curling articulations, the last of which termi- 
aa, tes in a book. The ventral surface presents two orifices : the one 
: ’ 1 the centre corresponding to a mouth, the other evidently intended 
'' r the discharge of the products of digestion. This animal is provided 
^ith g ve 
arms, which diverge directly from the centre plate or 
c,1] rass. The branches of these arms have ambulacra l grooves, com- 
Pjehending a double row of fleshy tentacles, in the centre of which is 
a mbulacral groove, properly so called, clothed with vibratile oils 
These oils or hairs guide the current 
% 
° V ® r their whole surface. 0 _ 
uick drives the various substances on which it feeds ; such as the 
^■ganic corpuscles of sea-weeds, and microscopic animalcules floating in 
6 s ea, towards its mouth. They are also powerful aids to respiration. 
^ The movements of these curious creatures are very slow, their only 
ject being to catch the bodies of animals and marine plants, or, by 
^ending or contracting their arms, to feel their way through the 
^ a ter to some new locality. Sometimes, also, in order to change their 
e< 3ding-g rouil d j the Comatula abandon the submarine forests, herbage, 
aU( t sea wracks ; and float through the water, moving their arms with 
c °Dsiderable rapidity in search of a new station. 
The Mediterranean Comatula (Fig. 109) is largely diffused on the 
Nepean shores of the Mediterranean. Its spreading arms extend 
0 three or four inches ; its colour purple, shaded, and spotted with 
he upon the ventral surface. 
