ENTOMOSTRACA. 197 



would appear at once a great number of these luminous 

 bodies, which retained their brilliant appearance for a few 

 seconds, and then all was dark again. They evidently ap- 

 peared to have it under their own will, giving out their light 

 frequently at various depths in the water, without any agi- 

 tation being given to the bucket. At times might be seen 

 minute but pretty specks of light darting across a piece of 

 water, and then vanishing; the motion of the hght being 

 exactly that of a Cyclops through the water. Upon remov- 

 ing a tumblerfuU from the bucket and taking it to the 

 light, a number of Cyclopes were accordingly found swim- 

 ming and darting about in it." These observations lead to 

 the conclusion that the large globes of light were Medusae, 

 and that the more generally spread flashes were occasioned 

 by the lanterns of thousands of minute Entomostraca. 



Entomostraca, 



The minute Crustacea described under this name include 

 many species of exceedingly different forms and habits. 

 They are found in ponds and ditches in great numbers, as 

 well as in nooks and corners of marine tide-pools, and the 



