530 
MOLLUSCA. 
and thus, as the fishermen say, it perishes by suffocation. Oppian, fifteen hundred years ago, 
charged the star-fish with similar atrocities : 
" The prickly star creeps on with fell deceit, 
To force the oyster from his close retreat. 
When gaping lids their widen' d void display 
The watchful star thrusts in a pointed ray ; 
Of all its treasures spoils the rifled case, 
And empty shells the sandy hillocks grace." 
ISTor have we even yet mentioned all the calamities of the oyster ; the insidious Drill — Fusus 
cinereus — punctures their shells by thousands, nay, by millions, and thus extracts the juices on 
which life depends. Many parts of the sea are paved with shells, bearing evidence of these sub- 
marine enormities. We need not pause to consider how like all this is to what we witness in 
every human town or city, where we constantly behold the shells of men who have been uncon- 
sciously drilled and sucked dry by the various kinds of sharp, sly, insidious Fusi Cinerei which 
live and breathe and have a fat, prosperous, and respectable being, among men. 
€lum TI. TUNICATA, 
These animals present the appearance of shapeless gelatinous masses ; they are composed of 
two tunics : the outer one is the mantle, and the inner one lines a large respiratory cavity. 
They are divided into two orders, the Bijyhora and Ascidice. 
ORDER 1. BIPHORA. 
This includes a group of free, swimming animals, usually of a glassy transparency, the bodies 
of which may be compared to a tube furnished with tAvo openings, one for the entrance and the 
other for the exit of the water. Those of the genus Salpa possess an elastic external membrane, 
so transparent that the whole interior structure may be seen through it ; by the contractions and 
expansions of this jets of water are created, which cause the animal to move along. The Salpse 
are divided into Aggregate and Solitary, but these are only difi'erent states of the same species. 
They are minute animals, sometimes seen floating on the sea in long chains. 
ORDER 2. ASCIDIiE. 
Forbes, in his "British Mollusca," says : "Rarely is the dredge drawn up from any sea-bed at 
all prolific in submarine creatures, without containing few or many irregularly-shaped, leathery 
bodies, fixed to sea-weed, rock, or shell, by one extremity or by one side, free at the other, and 
presenting two more or less prominent orifices, from which, 
on the slightest pressure, the sea- water is ejected with great 
force. On the sea-shore, when the tide is out, we find similar 
bodies attached to the under surface of rough stones. They 
are variously, often splendidly colored, but otherwise are 
unattractive, or even repulsive in aspect. These creatures 
are Ascidice, properly so called. Numbers of them are often 
found clustering among tangles, like branches of some strange 
semi-transparent fruit. They are very apathetic and inactive, 
living upon microscopic creatures drawn in with currents of 
water, by means of their ciliated respiratory organs. The 
leathery case is often incrusted with stones and shells, deco- 
rated with parasitical, though ornamental plumes of coral- 
lines, and not seldom perforated by bivalves, which lodge 
themselves snugly in the tough but smooth skin." 
MASS OF COMPOUND ASCIDIANS MAGNIFIED. 
