PREFACE. 



IN preparing for publication by the Ray Society 

 Alder & Hancock's * British Tnnicata ' I found it 

 necessary to compile a bibliography of works treating 

 of British species which had appeared up to the time 

 the authors ceased their labours on the Class. Joseph 

 Alder died in 1807, Albany Hancock in 1873, and as 

 he appears to have ceased to work at their MS. a few 

 years after the death of his coadjutor, the end of the 

 year 1870 seemed to be the best time to close all 

 references to the species described. 



The preparation of the present Bibliography was 

 therefore undertaken in the first instance to that date 

 for my own use only, but as other works besides those 

 relating to British species were included, and in the 

 course of its compilation it was found to have added 

 many references to any previous bibliography of the 

 Tunicata, it appeared to me that it might be useful to 

 others if printed. 



On suggesting this to Canon Norman, who was then 

 giving me his advice and assistance in preparing for 

 the press Alder & Hancock's monograph, he said that 

 a bibliography of works which had appeared since the 

 date named would be far more useful. 



That was in the year 1906, when my idea was to 

 make the bibliography merely a Supplement to the 

 third volume of the ' British Tunicata.' I then com- 



