Classification of the S/nders. 307 



from each other than from genera belonging to another family, 

 nay, even another tribus {A, p. 353) ; and the aforesaid con- 

 dition is only fulfilled, among the seven tribus, by the Terri- 

 telarise, and approximately also by the Laterigradaj and the 

 Citigradas. The Orbitelaria3 contain, as an alien element, the 

 Uloboringe ; the Retitelarite the genus Pachygnatha ; the Sal- 

 tigradas the family Eresoidce ; the Tubitelariaj are composed 

 of the highly heterogeneous families Agalenoida?, Filistatoidse, 

 Dysderoidse, and Drassoidfe (-S, pp. 335 and 336), and 

 form a receptacle into which all those forms have been 

 thrown that could not find a place in the other tribu^ 

 (Z?,p.345). 



2. Of a natural system of classification it may be required 

 that the groups regarded as coordinate ('' gleichwerthig ") 

 should really have the same systematic value ; but this is not 

 the case with the aforesaid tribus : the Territelarife, for in- 

 stance, correspond in value to all the other tribus taken 

 together (5, pp. SQ and 87) . 



3. The characters employed to distinguish the different 

 tribus are partly (for instance, Orbitelario3 and Retitelariaj) of 

 a very subordinate nature, and even then liable to exceptions, 

 partly not indicated at all or not given with sufficient sharp- 

 ness {-B, p. 334). The insufficiency of the hitherto received 

 classification shows itself in the vacillating opinions as to the 

 family in which various genera ought to be placed [A^ 

 p. 353). 



4. The denominations Orbitelari^, Retitelariee, &c. are not 

 systematic categories, but only names that indicate a biological 

 peculiarity (Z?, p. 336). 



Briefly, then, the tribus adopted by me are (1st) neither 

 natural, (2nd) nor of the same value, (3rd) nor distinguished 

 by sufficiently important or distinctly expressed characters ; 

 and, 4th, their names are inappropriate. 



In so far as these criticisms are directed against the 

 classification adopted in my work ' On European Spiders,' it 

 should first of all be borne in mind that it was not my in- 

 tention in that work to give a complete characterization of the 

 different tribus, but only to adduce, concerning those groups, 

 as much as appeared to be, at that period, necessary and 

 sufficient for the referring of a given family or genus to the 

 tribus to which it was believed to belong ; it should further 

 be observed that in tiiat work the principal stress was laid on 

 the Earo2)ean forms, the disentanglement of the synonyms of 

 which was its chief object. It was supposed that the cha- 

 racters which had been given of the groups in question by other 

 authors, and especially by Westring, were known to the 



