18 Richer — Dates of St. Petersburg Memoirs. 



9 2 : 55-82. Neue oder unvollstandig bekannte Pflanzen aus dem nord- 

 lichen Theile des stillen Oceans. Yon F. J. Ruprecht. pi. 1-8. 

 Nov., 1855. 



Unfortunately very few libraries as yet have realized the im- 

 portance of binding signature covers, either in their original 

 position, or at the end of the volume. In the latter case, great 

 care must be taken to mark on the signature cover the numbers 

 of the included pages, as in some cases works issued in parts* 

 contain folios from different parts of a volume, or from differ- 

 ent volumes of the same work. It is also of great value, in deter- 

 mining priority in biological nomenclature, that the date of 

 receipt of books and periodicals containing natural history arti- 

 cles be stamped on one of the title pages. This is of special 

 value in works giving only the year of publication. Most of 

 our periodicals and some of the irregular scientific serials are 

 now giving the actual date of their publication. 



Search for data on the above series led through the Congres- 

 sional, Department of Agriculture, National Museum, Smith- 

 sonian Institution, Geological Survey, Philadelphia Academy, 

 Astor, Columbia University, New York Botanical Garden, Mis- 

 souri Botanical Garden, Boston Public, Massachusetts Horticul- 

 tural Society, American Academy, Harvard University, and 

 Boston Society of Natural History libraries. Most of these 

 institutions had more or less complete bound sets; but the 

 Boston Society of Natural History and Philadelphia Academy 

 libraries were the only ones containing any number of bound 

 signature covers of this series and these were very incomplete. 

 This is accounted for largely by the fact that most of these 

 institutions received their numbers at a time when the subject 

 of priority had not demonstrated the value of determining the 

 exact dates of publication. 



'e.g. Englt'i- und I'nmtl, Die Naturliche Pflanzenfamilien und Ascherson und 

 Graebner, Synopsis der Mitteleuropaischen Flora. 



