Xll THE HISTORY OF THIS WORK. 



with which the notice begins were in all cases up to 

 the time of his death written by Alder, as also for the 

 most part were the sentences which draw attention to 

 the chief distinguishing features, and affinities -with 

 allied species. 



Most of the coloured figures of the species have been 

 taken from the Plates which Alder had prepared for 

 his Catalogue. Unfortunately there was no description 

 of these plates forthcoming, and the identification of a 

 few of the figures has been attended with some diffi- 

 culty. There were also later drawings by him of new 

 species discovered up to the time of his death ; and a 

 few additional illustrations of varieties have been given 

 from some of Alder's drawings in my possession. 

 These were found in the portfolios which contained all 

 his natural history drawings (except the Tunicata), 

 which were most kindly given to me by Miss Alder 

 after the death of her brother. 



A. M. NORMAN. 



BERKHAMSTED, 



-J7//1 MurcJi, 1905. 



