MOLLUSCJOlDA. 
307 
twisting and untwisting themselves. The corpuscles which float round 
Ihe animal arc violently agitated, as if they were under the influence oi 
8 ome strong breeze. Unhappy, indeed, is the fate of the unfortunate 
ltl fusoria which chance leads at this moment into the fatal circle. 
In many species, observers have discovered a special organ called 
vibracule, which deserves our attention for a moment. It is a 
hollow filament, situated at the upper and outer angle of eacli cell, 
tilled with a substance which is at once fibrous and contractile, all- 
otting of some very remarkable movements, which occur regularly, 
^nd generally at very short intervals. At first the filament inclines 
'tself towards the base, trembles, oscillates, and seems to sink ; pre- 
sently it recovers itself, and inclines in the opposite direction, where it 
* e Peats the same operation with the same order and in the same time. 
' Uliat are the functions thus performed ?” asks Fredol. “ Are they, 
''e Would ask, independent up to a certain point of the will of the 
J ' r yozoairo ? What is their purpose ?” We think he answers, “ That 
ibis organ serves the purpose of cleansing, and especially that ol 
^''eijgtliening, the entrance to the cell. It even continues its move- 
ment after the animal has been mutilated or killed. The poor sickly 
dead creature continues to be defended hv its protecting vibracuie. 
The prey which is drawn into the vortex by the tentacles and their 
^Ppendages enters into the mouth, to which is attached a pharynx, 
sphagna, stomach, and intestines. In the hack or haemal region, 
not far from the mouth, there is a special opening for this intestine. 
Inspiration is provided for in the Bryozoaires by the ciliate appen- 
Ages which surround the mouth ; they are at once tentacula and 
br anchi8e. The animal presents no other trace of organs of the 
^es. A Hm .,n ganglion and a few fillets constitute all of the nervous 
System which can be traced; neither heart nor blood-vessels have been 
‘ound. 
The egg, in the case of the Bryozoaires, gives birth to a young 
A’hlaal covered wdth hairs on its surface ; it swims about freely until it 
‘^ chosen a convenient place in which it can establish the new colony 
I' hch it j s t 0 originate. But this choice is not made for itself alone; 
® young animal encloses under its hairy envelope two new indi- 
1 Ual Sj which, young as they are, have already the appearance ol 
Hit Bryozoaires. At first, these only increase the personnels oi 
6 colony by budding, hut in a short time they produce eggs. 
x 2 
