HYDRACHNA. 255 



to prosecute farther enquiries into the subject. But, I acsknowledge that 

 I did so with the less reluctance, after perusing the work specially de- 

 voted to it by the learned and industrious Otho Frederic Miiller, whose 

 writings, universally useful, must be always most highly prized by those 

 who can form a due estimate of their intrinsic value. 



The extensive knowledge displayed by MUUer was derived from that 

 best of sources, practical acquaintance with each individual species con- 

 stituting a genus, and that very often while many of them were yet in 

 the living state. Miiller, like Liunteus, seized on a few of the most 

 prominent features, those not difficult to be recognized ; but, if any thing 

 shall be regretted of Miiller, it is his anxiety for describing numbers so 

 great as to have left neither time nor opportunity for preserving his sub- 

 jects alive. 



Modern authors, however, perhaps less skilful, but more eager for 

 change, have ventured to dismember certain genera, or have left only an 

 inferior section to represent the whole. They have vainly endeavoured to 

 erect so many new systems from among the fragments. But mere de- 

 scription of the body, including anatomical details, Ijy entering on such 

 minutia; as none but some of the more modern naturalists would have 

 thought of, is insufficiently adapted for general information. Besides, 

 much remains for explanation ; for, the lower we descend for characters, 

 as the source of deductions, the less important features are obtruded to 

 view. 



The Hj/drachnce, to be literally interpreted Water Spiders, are very 

 beautiful animals, of delicate and symmetrical form, decorated with vivid 

 colours, agreeably interspersed. Their lively courses amidst their trans- 

 parent dwelling, the limpid element, combined with the diversity of 

 their appearance, render them amusing and full of interest. 



Miiller, who is still to be held the leading authority on the subject, 

 characterizes this genus generally, as engrossing animals distinguished by 

 eight feet, two articulated palpi, and two, four, or six eyes. 



The figures annexed to these observations, explain more amply that 

 the shape of the body is globular, ovoidal, or simple, with a prolongation 



