Vll 



London ' for 1907, which is the date on the title-page 

 of the volume, although that part was issued in May, 

 1908, a date which appears on the cover only. 



In such enquiries Mr. C. D. Sherborn's valuable 

 papers giving the dates of publication of works issued 

 at intervals have proved of great service. 



A glaring instance of wrong dating appears in the 

 'Archiv fiir Naturgeschichte,' all the volumes of 

 the bibliographical portion of which, from about the 

 year 1885, are dated some years before they were 

 published. Thus the date on the title-page of the 

 volume which gives a list of the literature on the 

 Tunicata for the years 1899 to 1902 is 1897. It 

 was issued in 1904, a date which only appears on a 

 corner of the cover. If that is not bound in with 

 the volume the date of publication is therefore lost. 



A frequent source of difficulty is the gathering to- 

 gether into one volume of several parts published in 

 different } r ears, the date on the title-page being that of 

 the last part published. In such cases, and they are very 

 numerous, an endeavour has been made to ascertain 

 the date of publication of the memoir cited, but not 

 always with success, and in all works recently examined, 

 when such date does not correspond with the date on 

 the title-page, that date has also been given after the 

 number of the volume. 



I have referred to this matter at some length in the 

 hope that these lines may be seen by editors of journals, 

 etc., published in parts, who have it in their power to 

 very much lighten the labours of a bibliographer by 

 giving, inside the volumes they edit, the date of 

 publication, month and year, of each part of which the 

 volume consists, adding for identification, if required, 

 the pages of the part. 



