CEUSTACEA. 217 



tildes of various species of Entomostraca, accompanied, perhaps, by the 

 larvae of higher Crustacea, Echinoderm larvae, Annelid larvae, and the 

 smaller Medusae. The water containing these should be put into a large 

 glass jar, freely exposed to the light; and, after a little practice, the eye 

 will become so far habituated to the general appearance and modes of 

 movement of these different forms of animal life, as to be able to distin- 

 guish them one from the other. In selecting any specimen for Micro- 

 scopic examination, the Dipping-tube ( 126) will be found invaluable. 

 The collector will frequently find Megalopa larvae, recognizable by the 

 brightness of their two black eye-spots, on the surface of floating leaves of 

 Zoster a. The study of the Metamorphosis will be best prosecuted, how- 

 ever, by obtaining the fertilized eggs which are carried about by the 

 females, and watching the history of their products. For preserving 

 specimens, whether of Entomostraca, or of larvae of the 'higher Crustacea, 

 the Author would recommend Glycerine- jelly as the best medium. 



