212 
COMPARATIVE ZOOLOGY. 
Fig. 177_Nauplius of Entomostracan ( Canthocamptus ). See Fig. 255. A, first an¬ 
tenna ; An, second antenna; a, anus; L, labrum; 0, ocellus; S, stomach. (From 
Brooks, after Hoek.) 
other words, the parent may find no resemblance to him¬ 
self in any of his progeny, until he comes down to the 
great-grandson.” Thus, the Jelly-fish, or Medusa, lays 
eggs which are hatched into larvae resembling Infusoria— 
little transparent oval bodies covered with cilia, by which 
they swim about for a time till they find a resting-place. 
One of them, for example, becoming fixed, develops rap¬ 
idly ; it elongates and spreads at the upper end; a mouth 
is formed, opening into a digestive cavity; and tentacles 
multiply till the mouth is surrounded by them. At this 
stage it resembles a Hydra. Then slight wrinkles appear 
along the body, which grow deeper and deeper, till the 
animal looks like “a pine-cone surmounted by a tuft of 
tentaclesand then like a pile of saucers (about a dozen 
