ECHINODEllMATA 
269 
e °Qsidered to be certain bright reel points which are situated at the 
extremity of the arras and on the under surface — a most singular 
position for the organs of sight. The eyes must, besides, be very 
’’''perfect, for they possess no crystalline. Ehrenberg insists upon 
existence of eyes in some species, attributing the function to those 
r od spots however ; while llyinor Jones attributes the indications in 
"'hich this originates to an extremely delicate sense of touch in the 
^ '-fishes. Professor Edward Forbes, while he admits the existence of 
8 ai 'glions hr the nervous system to be extremely doubtful, seems, by 
^'e frequent use of the terms eye and eyelids, to admit that the 
s Pecks to question were visual organs ; the weight of authority inclines 
Wefore to Ehrenberg’s view, that if not eyes in the strict sense of 
!J I<; term, they serve the purposes of vision, modified and adapted to 
tae Wants of the animal. 
The star-fishes have distinct sexes, with individual differences ; their 
which are round and reddish, undergo curious phases of develop- 
j ft(;t 't. They produce little worm-like creatures, covered with vibratile 
| a 'rs, liE e infusoria, which swim about with great vivacity^ ; these 
P tie creatures are subject to considerable changes. In the year 183.) 
' Sars described, under the name of Bipinnavia a st wig era, an enig- 
matical animal resembling a polype from the arms at one extremity of 
6 hnly, while the other terminated in a tail, furnished with two fins ; 
but 
e "tr, 
SOi 
it was chiefly remarkable as having an Asterias attached to the 
'emity which carried the arm; he expressed an opinion, vdiich was 
placed beyond any doubt, that this bipinnaria, was an Asterias in 
°°Urse of development. The egg becomes a sort of infusoria, the 
s oi'ia becomes a bipinnaria, and this produces the Asterias. In 
the bipinnaria does not become an Asterias by any metamorphoses 
'ts 
if'fui 
short 
ar ’ a iogous to that so well known amongst insects — the butterfly, for 
,;-ple^but becomes, so to speak, the foster-mother or nurse to the 
T'nnaria. The larva is large, and it is at the cost of a very small 
^ er "al rudiment of this larva that the Asterias is developed : the 
^/ r 'us robs the larva of its stomach and intestines, and turns it into 
t ' l8c eral apparatus for its own use. But the Asterias makes itself a 
°f any of the pieces most remote from the primitive mouth ot 
• 6 l^va. Thus the bipinnaria divides itself ; it gives its stomach and 
Ul test: 
anes, 
, and keeps its cesophagus and mouth, and it can live several 
dys atte r the Asterias is detached from it. 
