On the Young Stages of a few Annelids. 305 



embryo Mollnsks, both very different in appearance and in 

 their habits from the adults. 



From the few complete embryologies we possess of the lower 

 marine animals, it is apparent that there has not been, up to 

 this time, any systematic method of working. Artificial fecun- 

 dation can do much towards adding to our knowledge of the 

 early stages of marine animals, but any one who has lived at 

 the sea-shore and endeavored to keep alive these tiny crea- 

 tures, will soon find in this method insurmountable obstacles 

 to pursuing his investigations beyond very narrow limits. The 

 only way is to go to the fountain head at once, to make one- 

 self familiar with the currents at all hours of the tide and under 

 all possible influences of wind ; to notice the place where 

 opposite currents meet, and throw into long bands the wealth 

 of animal life they have swept along; to become so perfectly 

 familiar with what you may expect to find under certain con- 

 ditions, that no time shall be lost in looking for the most favor- 

 able spot which otherwise you would only stumble upon acci- 

 dentally. The habitat of the adult animals should be carefully 

 observed, so that by surface dredging with the fine gauze hand- 

 net in the vicinity of their abodes, and by a close attention to the 

 direction which the currents take from these places, at the time 

 of breeding, we can often obtain specimens at all ages and of 

 all sizes, till they have ceased to be nomadic or have assumed 

 the habits they retain in their adult condition. 



According to the nature of each locality spots are easily 

 found where the currents which skirt along the shores are com- 

 pelled to pass. Projecting points of land are barriers during 

 certain hours of the day, and everything brought floating with 

 the tide along their shores will accumulate, until it forces its 

 way round or over the obstacles. Narrow passages between 

 islets and the shore, through which the tide rushes with great 

 rapidity, will give us a synopsis as it were of all that can be 

 found in the vicinity. When the wind blows constantly from 

 the same direction, it will heap up on the lee shore anything 



