DORIS SPAWN. 225 



thick clusters, composed of the self-same objects! 

 Beside them were lying confused heaps of sea-slugs, 

 evidently exhausted with their hatching exertions. 

 Anything more repulsive to the eye than those 

 animal heaps exhibited it would be difficult to con- 

 ceive. Yet, at the same time, I know of no sight 

 more pleasing than to watch the Doris in its healthy 

 state, gliding along with outspread plume on the 

 under surface of the water, or up the sides of the 

 tank, more especially if it be observed through a 

 powerful hand lens. 



These remarks will perhaps convey some new in- 

 formation to the young naturalist, embracing as they 

 do the leading facts connected with the wondrous 

 embryotic development of many marine animals. 

 The reader will already be prepared to learn that the 

 vivacious little animal, moving by aid of cilia and 

 enclosed in a shell, was in reality the youthful stage 

 of that slow creeping gasteropod the Doris, which, in 

 its mature form, is possessed of no cilia, nor any 

 shelly covering whatever. 



I should not have introduced this subject so 

 familiarly did I not feel anxious to make my readers 

 aware how easy it is for each of them to conduct 

 experiments in the early stages of embryotic develop- 

 ment, and to gain practical evidence of the wonders 

 which this study unfolds. 



' What/ eloquently asks Mr. Lewes, ' can be more 

 interesting than to watch the beginnings of life, to 



