204 Mr. A. Agassiz on the Young Stages 



net ; he has been followed with eminent success by many of his 

 pupils, and now scooping the surface of the sea in search of 

 diminutive animals, scarcely to be recognized with the naked 

 eye, is one of the most profitable sources of supply for recent 

 investigators at the sea-shore. Baur* has introduced fishing 

 with the gauze net by sinking it to any desired depth ; and this 

 promises to be a fruitful mode of finding what cannot be reached 

 with a hand net. Meyer and Mobiusf, in their investigations 

 of the Fauna of the Bay of Kiel, have even attempted, with re- 

 markable good fortune, to pump up from the vicinity of the 

 bottom any animals there abounding. 



As a rule, the habits of the young marine animals are so 

 utterly different from those of the adult, that we cannot expect 

 to find them together, and must not search for the young in the 

 retreats where lie concealed the adult Crustacea, in the mud 

 flats or sandy beaches where are buried Annelids and Mollusca, 

 along the rocky shores where so many Gasteropods abound, or 

 under seaweeds and stones, the hiding-places of both Annelids 

 and Mollusks as well as Crustacea. We must not look in 

 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, Goosefish, Lumpfish, 

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

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

 fishes abound close inshore, along sandy flats heated by the 

 sun, seeking to avoid the dangers which would beset them in 

 deeper waters; and they can scarcely be recognized 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 Hydroid Medusee, when> 

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

 rise to Medusae endowed with the most varied and graceful 

 movements, and often carried about helpless by the wind and tide. 



* " Beitrfige zur Naturgeschichte dcr Synapta dlgitata/* in Verhandl. 

 der K. L. C. Akad. : 1864. 

 t Fauna der Kieler Bucht. 



