304 On the Young Stages of a few Annelids. 



rocky pools frequented by Starfishes, Sea-urchins, and the like, 

 for young Echinoderms ; the young Polyps are not always to 

 be found growing up by the side of their parents; neither can 

 we expect to find the young Cod, Goose-fish, Lump-fish, 

 Flounder, Cottoids, and Perches, on the feeding-grounds fre- 

 quented by the fishermen in search of the adult. The young 

 fishes abound close in shore, along sandy fiats heated by the sun, 

 seeking to avoid the dangers which would beset them in deeper 

 waters, and they can scarcely be recognised for what they 

 really are except by the most practised eye. Thus the earlier 

 stages of most marine animals are passed under circumstances 

 totally different from those of the adult. When the adults are 

 sedentary in their habits, and capable of very limited motion, 

 the young are almost always endowed with corresponding 

 freedom, leaving them entirely at the mercy of the winds and 

 currents. On the contrary, in the class where we have the 

 greatest freedom of movements and least sedentary habits, we 

 find the young, for the most part, fixed to the ground and 

 incapable of any motion. What greater contrast can there 

 be in this respect than the early stages of ITydroid Medusae, 

 when, plant-like, they remain for ever attached to one spot, 

 giving rise to Medusas endowed with the most varied and 

 graceful movements, and often carried about helpless by the 

 wind and tide. 



The young of many of our Annelids present a similar con- 

 trast to the adult, the latter passing their existence buried in 

 tubes sunk in the mud or sand, while in their early stages they 

 are free and nomadic, and swarm near the surface of the sea. 

 Who would have thought of looking for young Echinoderms 

 among those erratic beings which perform such a conspicuous 

 part in the phosphorescence of the sea, until the wonderful 

 researches of Miiller led the way to a field of investigations 

 which has revealed changes of the most astonishing nature ! 

 The young Crustacea, until quite advanced, find their way to 

 the top of the water, where they swim about in company with 



