hanskn: on six speciks ok koenenia. 233 



is to describe.» But when the author publishes this extract from 

 one of my letters as a contribution to the knowledge of the 

 distribution of the order, it had been very proper to publish 

 more details from my letters to Prof. Whkfjj-ir and herself. 



On p. 615 — 16 the author says: •» Koenenia has since been 

 found in Siam and Paraguay and, like all archaic types, it will 

 doubtless be found to be cosmopolitan in its distribution.» Many 

 curious things have been written on types supposed to be »archaic». 

 It has not been proved by any palaeontogical fact that the order 

 Palpigradi is a very old type, and I for one can not see that 

 it necessarily must be so. Furthermore it is (juite impossible to 

 draw a conclusion as to the age of a type from the fact that it 

 is cosmopolitan, or to conclude from the age to the extent of 

 geograjihical distribution. Such groups as Miiscidce, Oniscidœ 

 and other types have a world-wide geographical range, and they 

 are scarcely considered as archaic forms. Several authors believe 

 that the restricted distribution of some types is well explained 

 by the assumption, that they are remnants of a comparatively 

 ancient or even archaic fauna. The order SympJiyla is perhaps 

 a very old type, but I can scarcely believe that this is the case 

 with the order Pauropoda : both types contain only small animals 

 which live on the same localities, and both are probably almost 

 cosmopolitan in their distribution. At the present time we know 

 too little or nothing about many things, which it is necessary to 

 be acquainted with before we are able to draw inferences as to 

 several questions of this kind. 



The major part of the paper deals with the internal anatomy 

 of A'. Whceleri. Of this chapter no extract will be commu- 

 nicated here — with exception of some criticism of the state- 

 ments on the ventral sacs and two other points — and I refer 

 the reader to the treatise itself. When Mr. Borner has published 

 his paper on the anatomy of A', mirabilis^ and when we have 

 obtained more complete information on the internal structure of 

 the Pedipalpi etc., it will be possible to compare the internal 

 structure of the various orders of Arachnids. 



Miss RucKER spends about five pages on the description of the 

 »external) anatomy of A'. WJieeleri, especially pointing out the 

 differences between the two sexes and most of the differences 



41 



