144 
LECTURE X. 
sufficient accuracy. The figures hitherto given, 
such as that in Sloane’s Jamaica, and some other 
works, exhibit only a general similitude. It is often 
confounded with a different species, resembling 
it in some degree, but of a much longer or more 
slender form, and of a greenish colour, with nu- 
merous yellowish-brown tentacula, among which 
are two or three central ones far exceeding the 
rest in size and length ; of a wrinkled or annu- 
lated appearance, and of the richest deep-blue co- 
lour. The real structure or anatomy of these ve- 
sicular Holothurige seem as yet but very imper- 
fectly understood. They are observed to float oc- 
casionall}^ during fine weather, on the surface of 
a calm sea, and when taken, have the power of in- 
flaming the skin to a considerable degree, if in- 
cautiously handled. 
The beautiful genus Actinia, from its flower- 
like appearance when expanded, called the Sea^ 
Anemone, is characterized by having an oblong- 
body, of an extensile and expansile nature, and 
adhering by the base to rocks or other marine 
substances. The m.outh is situated in the centre 
of the upper part or disc, and is surrounded by 
very numerous, soft, extensile feelers or arms. 
