HISTORY OF PLUTEUS PARADOXUS. 197 



and on separating a portion of the under surface, the 

 eggs, of a vivid red, are seen adherent to it. The 

 colour is so bright, that the under surface of the disc 

 is sensibly affected, and the space between the rays 

 occupied by the spawn becomes ruddy. The spawn 

 is composed of ovoidal capsules confusedly huddled 

 together. 



But the most interesting part of the history of the 

 Ophiuri is the wonderful metamorphosis through 

 which they have to pass, during their progress from 

 the egg to their mature condition. 



The young Ophiurus on leaving the egg presents 

 itself under a most grotesque aspect, in which con- 

 dition it has long been known to naturalists, and de- 

 scribed under the name of the Pluteus paradoxus, or 

 Easel-animalcule, from its resemblance to a painter's 

 easel, without however the slightest idea being enter- 

 tained of its ultimate destiny. 



The Pluteus paradoocus (PI. IV. fig. 1, a, b, c) is 

 exceedingly minute, being not more than f ths of a 

 line in length. When highly magnified, its body is 

 seen to have somewhat of a conical shape, terminating 

 above in a point, but dividing inferiorly into eight 

 long processes or appendages of various dimensions, 

 to which it owes its peculiar figure. Each of these 

 processes is supported by an internal calcareous 

 framework, which, branching in different directions, 

 forms a basis whereon the soft parts are spread out. 



The whole animal is perfectly transparent, its sub- 

 stance resembling dull glass the apex of the body 

 and the extremities of the arms or processes being 

 slightly tinged with orange. 



