THE LIVING WORLD. 
4i 
being classed under the head of branchiata (many-armed), 
numerous branches into which the creature is divided, like those 
the above, both 
because of the 
•of a plant. 
The Shield Porcupine ( Clypeaster rosaceus) is a member 
•of the very large family under which the sea-urchins are 
•classed. The species here specially named is about the size 
of a silver dollar, and presents many beautiful markings which 
make it an interesting study, the most curious being the 
prickly spines with which it is covered, from whence the 
name is derived. ' It is not a very common spec’es, and 
appears more frequently on the Pacific coast. 
The Finny-Legged Mollusk (. Hyalea tridentata ) is 
remarkable, because, like the glow-worm, it lights up the 
darkness of the night. 
SHIELD PORCUPINE. 
(1 Clypeaster rosaceus.) 
TUBULAR HOLOTHURIA {H. tubulosa ). 
The True Kauri ( Cyprcza moneta) is used in Africa as currency, and this 
fact has established its capture and exportation as a commercial interest. 
The Grape Mollusk ( Botryllus ) is peculiar, 
because though an apparently single star-fish it 
is really a community of many individuals which 
Lave, with the exception of the organs of respi¬ 
ration, individual development. 
The Tree-like Snail (. Dendronotus arbor- 
^scens) has shrub-like gills upon the back, while 
its tentacles take the semblance of the true gills. 
The Edible Mussel ( Mytilus edulis) is dis¬ 
tributed with the greatest profusion throughout 
European waters, and an unexpected encounter 
as it clings to its support is 
very lacerating to the feel¬ 
ings of a human being. Its 
value as food is more than tree snail. 
open to question, but it is 
always good to “ feed fish withal.” 
We now hasten on to the next higher form, which, in 
the most natural sequence, will be 
T«E CRUSTACEA. 
hyalea tridentata. 
Under this heading are classed those creatures that have 
a shell covering, or crust, in both legs and body, and which breathe by gills, 
and not by air tubes, as do the Cephalopods. To this order belong a large 
