Classification of the Spiders. 305 



characteristics a systematic value is, on the contrary, but 

 rarely attributed. 



If I undertake here to offer some critical remarks on Dr. 

 Bertkau's now-mentioned views, I do so with great hesi- 

 tation, and because I have in vain waited for some person 

 more competent than myself, or at least more versed in the 

 anatomy of the Spiders, to undertake a review of Dr. Bertkau's 

 works on the classification of this group of animals. These 

 works (of which the most important, ' Versuch einer natur- 

 lichen Anordnung der Spinnen'*, was published nearly eight 

 years ago) are indeed worthy of the greatest attention, not 

 only of every arachnologist, but of zoologists in general ; for 

 besides being of great interest from a classificatory point of 

 view, they are rich in new and important observations on the 

 life-history and the anatomy of the animals on which they 

 treat. Dr. Bertkau is, as is generally known, a most saga- 

 cious and learned entomologist ; he has, more especially in 

 the field of arachnology, enriched his science not only with 

 good works of a systematic, descriptive, and zoogeographical 

 character, but also with many anatomical and biological dis- 

 coveries of great importance ; it is, for instance, to Dr. Bertkau 

 that we are indebted for our knowlege of the principal parts 

 of the male organs of copulation in Spiders, and of the functions 

 of these parts, of which we had formerly only imperfect and 

 erroneous notions. 



Before entering on the examination of Dr. Bertkau's spider- 

 system I ought perhaps to try to give an answer to the criti- 

 cisms which he has directed against the method now-a-days 

 most generally adopted of classifying the animals in ques- 

 tion, and especially against the classification adopted in 

 my Avork ' On European Spiders.' That this classification 

 should, in many points, be modified and improved, and that 

 some of Dr. Bertkau's criticisms are fully justified, I am, 

 however, the first to acknowledge. 



The considerable progress which arachnology has made 

 during the last quarterof a century must of course have exercised 

 a modifying influence on the attempts at a natural classification 

 of the animals before us ; but it cannot well be said that tliis 

 progress has made the solution of the problem more easy than 

 it formerly was. The difficulties which here present them- 

 selves depend, as Bertkau [A, p. 352) justly remarks, chiefly 

 on the body of the spiders being (compared with that of in- 

 sects and crustaceans, for instance) but little differentiated, or 



* In the following pages, when citing this * Versuch ' and the treatise 

 'Ueber das Cribellum und Calamistrum ' (see above, p. 304, footnote), I 

 shall, for the sake of brevity, call the former work A and the latter B. 



