COLLECTING CRUSTACEA 971 



the fresh-water species, and the tow-net for the marine. In localities 

 favourable for the latter the same ' gathering ' will often contain 

 multitudes of various species of Entomostraca, accompanied perhaps 

 by the larva? of higher Crustacea, echinoderm larva?, annelid larvae, 

 and the smaller JlcJus" . 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 appear- 

 ance and modes of movement of these different forms of animal life 

 as to be able to distinguish them one from the other. In selecting 

 any specimen for microscopic examination the dipping-tube will be 

 found invaluable. The collector will frequently find Megalopa larvae, 

 recognisable by the brightness of their two black eye-spots, on the sur- 

 face of floating leaves of Zostera. The study of the metamorphosis 

 will be best prosecuted, however, by obtaining the fertilised eggs, 

 which are carried about by the females, and watching the history of 

 their products. For preserving specimens, whether of Entomostraca 

 or of larva? of the higher Crustacea, the Author would recommend 

 sterilised glycerin-jelly as the best medium. 



interesting facts and speculations on the Crustacea will be found in P. Mailer's Facts 

 <i ml Ari/itmoit? fur Darwin (London, 1869). The work of Reicheiibach on the 

 Development of the Crayfish is contained in vol. xxix. of the Zeitschr. f. wiss. Zool. 

 p. 123, 1877, and vol. xiv. of the Abhandl. Senckenlerg. Naturf. Gesells. 1886. See 

 also the essay, by W. K. Brooks, On the Development of Lucifer, in Phil. Trans. 

 1882, p. 57. Mr. F. H. Herrick's memoir on the American Lobster (Bull. U.S. Fish. 

 Comm. xv. [1895] ) contains matter of much interest. Professor Sars's fully illustrated 

 monograph of the Crustacea of Norway is being steadily and rapidly published. 



