MOLLUSCOlDA. 
309 
hv ° °r three in breadth,” says Sir J. G. Dalyel, “ of a flattened figure, fine 
translucent green colour, and fleshy consistence. Some of the shorter 
en d to an elliptical form, hut those of larger dimensions are linear, 
"ith parallel sides and curved extremities. The middle of the upper 
atl d the whole of the under surface are smooth, the former somewhat 
®°Hves, occasioned by a border of seventy or eighty, even up to three 
hundred and fifty, individual polypi, dispersed in a triple row, their 
Hump - • - .... ■ - 1 - 
these 
>er depending entirely on tire size of the specimen. Each of 
numerous polypi, though an integral portion ot the common 
is a distinct animal, endowed with separate action and sensation, 
he body rising about a line above a tubular fleshy stem, is crowned by 
a head, which may be circumscribed by a circle as much in diameter, 
0 a horse-shoe shape, and bordered by a hundred tentacula. Towards 
side, the mouth, of singular mechanism, seems to have projecting 
‘is and to open as a valve, which folds up within, conveying the 
Particles which are absorbed to the wide orifice of an intestinal 
11 San, which descends, perhaps, in a convolution below ; and returns 
a S a in, terminating in an excretoiy canal under the site of the tenta- 
c ul a .” 
The inhabitants of the colony are then united in great numbers 
'hder one common envelope ; these are longish filaments of the size 
a swan’s feather, re- 
ading one of the appear- 
^ Ce of the silk thread 
°*n by embroiderers 
ass chenille. The downy 
a PP e arance is produced by 
collection of tentacula 
e ° u ging to this curious 
s War m . 
^ass 
Fig. 122. Cristatella mucedo (Cuvier). 
The filamentous 
is the translucent 
r °' v °1 cells in which these 
'^j'Dialcules are lodged, and to which they retreat when disturbed. 
hes e ce p g are some ti me s free in part, sometimes completely rooted to 
16 s tenis of aquatic plants. The tentacles are of a fine transparent 
colour, the body being of a brown colour. Fig. 122 represents 
'mucedo which is common both in this country and m 
bailee. 
