254 HYDRACHNA. 



CHAPTER VI. 

 THE HYDRACHNA, OR WATER SPIDER. PLATES LXVI1L, LXIX. 



THE genus Hydrachna comprehends a race of small carnivorous 

 animals, exclusively aquatic, bearing considerable resemblance to the 

 Crustacean tribe, which we have just quitted. They also exhibit cer- 

 tain prominent habits, in common with those of terrestrial Spiders. 



But there are various distinctions in form and proportions, in gene- 

 ral organization, and animal propensities, altogether affording such a 

 modification of distinctive features, as to constitute sufficient elements of 

 a separate genus, whereof I shall at present endeavour to avoid all prolix 

 discussion. 



Some of its characters are quite obvious, others much less so. Thus, 

 although equally ravenous, fierce, and cruel, with the boldest, I am yet 

 unacquainted with any species among the Hydrachnse, lurking in quies- 

 cence for concealment, during the approach of prey, or of constructing a 

 snare for the unwary victim. 



Nevertheless, independently of the figure, there is much correspon- 

 dence in many things between the Crab, the Spider, and the Hydrachna. 

 The beholder cannot but be impressed with their general similarity of 

 shape, and with the same ferocious disposition, as belonging to predatory 

 animals, and demonstrated in the employment of destructive organs to 

 attain their purpose. 



Having had very favourable opportunities for observation, a number 

 of years ago, though subsequently interrupted, I ceased for a long time 



