592 BRITISH ORIRATIDJ]. 



and in the Tm'sonemidce the sexes are so different from 

 each other that no one would suppose them to belong 

 to the same species, or, perhaps, even the same family, 

 whereas in the Oribatidce it is impossible to distinguish 

 one sex from the other without seeing the internal 

 reproductive organs. 



In vol. i. (p. 60) I mentioned that I used the dis- 

 tinction of monodactyle and tridactyle claws with 

 reluctance, fearing that later discoveries might invali- 

 date it ; I only used it to a small extent. My fears 

 have been justified by the discovery of some mono- 

 dactyle species of Nothms, &c. I have therefore 

 thought it best to reduce the monodactyle and tridac- 

 tyle distinction to a specific instead of a generic value 

 as far as possible, even though the distinctions which 

 take the place are not so convenient ; I, therefore, sub- 

 mit the following amended table for the identification 

 of genera (to be used instead of that at page 64), in 

 which I have eliminated the claw question in every case 

 except that of Tegeocranus, where it is difficult to see 

 what is to supply its place. I have also made a few 

 other trifling alterations ; thus the genus H)j2)Octhonms 

 is defined so as to include some species discovered since 

 the publication of vol. i. 



