NATURAL HISTOEY 



BRITISH ENTOMOSTRACA, 



INTRODUCTION. 



IN this monograph I have retained the name Entomo- 

 straca, using it to comprehend all those minute Crustaceans 

 described by Miiller under that name, with the various 

 additions which have been made since his time by 

 Latreille, Leach, and others., to that particular group of 

 curious little animals. To none of the Crustacea has so 

 little attention been paid by British naturalists as this 

 division, though there are few deserving of more attentive 

 study. The exceeding minuteness, and the extreme de- 

 licacy of structure of the great proportion of them, have 

 perhaps been the causes of this neglect, deterring most 

 naturalists from examining and studying them as they 

 require to be studied fresh from their native habitats. 

 The difficulty of preserving them obliges the naturalist to 

 seek them in their secret lurking-places, the fresh-water 

 ponds and ditches, and the little pools in the rocks on 

 the sea-shore, where they are chiefly to be found, or on 

 the fishes to which they adhere as parasites, and to study 

 them, as it were, upon the spot, with the aid of his mi- 

 croscope. The external appearance, however, alone of 

 many of these interesting little creatures is enough to 

 excite the curiosity and rouse the attention of the natu- 

 ralist. Some of them are so like small bivalve shells, 



i 



