DEVELOPMENT OF EOLIDS. 259 



lusc, and undertook the office of finding food for 

 both. 



Passmg from the region of vases and pie-dishes, let 

 us enter that of wide-mouthed bottles, not so attrac- 

 tive to the imlearned eye, but full of j^romise to the 

 mind which sees there Polypes, Polyzoa, and ova. For 

 these we want the microscope, one of those "■ intellec- 

 tual tubes which give thee a glance of things that 

 visive organs reach not ; " '"' and many a blissful hour 

 may we spend over its revelations. We may hear, 

 indeed, that our perplexed vassal reports us as spending 

 the day " a-squinting through a glass ; " but her sar- 

 casm is harmless, and the revelations are thrillino-. 

 What can be more interestino- than to watch the beo-in- 

 nings of Life, to trace the gradual evolution of an animal 

 from a mass of cells, each stage in the evolution present- 

 ing not only its own characteristics, but those marks of 

 affinity with other animals which make the whole world 

 kin ? To watch the formation of blood-vessels, to see the 

 heart first begin its tremulous pulsations, to note how 

 Life is, from the first, one incessant struggle and progress 

 — these keep us with fascinated pertinacity at our study. 



Among other things, I have watched the develop- 

 ment of the Eolis and Doris with great interest ; not 

 the less so from the fact that, in spite of the marked 

 difi'erences between the developed animals, their course 

 of development is so indistinguishably similar. On the 

 rocks, or on the side of your vases, you may see a long 

 coil of spawn, looking like delicate pearl beads enveloped 



* Sir Thomas Browne. 



