KEPORT OF THE SECEETAEY. 13 



Collections"; and the third, the "Annual Reports of the Eegents" of 

 the Institution. The works of the first class, the Smithsonian Contribu- 

 tions to Knowledge, are published in quarto form, and are intended to 

 embrace original memoirs, either the result of special investigations 

 authorized and directed by the Institution, or prosecuted under other 

 auspices and presented to it. The works of the second class, the Mis- 

 cellaneous Collections, are similar in plan and construction to the " Con- 

 tributions," but are in octavo form, and embrace more particularly mono- 

 graphic and descriptive papers in natural history, formal or systematic 

 lists of species of animals or plants, physical tables, reports on the pres- 

 CHt state of knowledge in some department of physical or biologic sci- 

 ence, &c. As with the "Contributions," each volume is composed of 

 several distinct and independent papers, having no necessary connection 

 with each other, the collection being determined chiefly by the aggregate 

 number of pages suitable for a volume of average size. The average 

 number of pages in the quarto volume is about 600; in the octavo volume, 

 about 800. Each paper or memoir in either class is separately paged and 

 indexed, with its own title-page, so as to be complete in itself, and sepa- 

 rately distributed according to its subject. Of the quarto "Contribu- 

 tions," twenty-one volumes, and of the "Collections," fifteen volumes 

 have been published. 



The Smithsonian annual reports commenced in 1817, and being made 

 to Congress, are published by that authority, and not at the expense of 

 the Smithsou fund. The earUer reports of the Secretary were printed 

 in smaU pamphlet editions, but were collected and reprinted with the 

 report for 1853, and with this the series of bound volumes may be said 

 to have begun. The number, or edition, ordered by Congress has varied 

 from year to year, but the proportion of copies placed at the disposal of 

 the Institution has been distributed to its correspondents as fuUy and 

 liberally as possible. 



Smithsonian Contributions to Knowledge piMisJied in 1878.— For sev- 

 eral years past the Institution has had in its archives a paper by the 

 late Prof. Henry J. Clark, relating to the Lucernariai, an extremely in- 

 teresting group of marine animals closely allied to the Acalephs, or 

 Jelly-fish. The death of the author before the work could go to press, 

 and' the difficulty of finding any one wilhng to undertake the editing of 

 it, prevented immediate action on the memoir; but Prof. A. E. VerriU hav- 

 ing agreed to take charge of the work, it was at length put to press, and 

 was finally published in 1878. The memoir consists of 138 quarto pages 

 and eleven plates, and it has been distributed to the leading zoologists. 

 The Institution is under great obligations to Professor Verrill for the 

 careful and critical supervision of the typographical execution of the 

 work, as weU as for some important notes and rectifications. Mr. 

 Samuel P. Clark, of Johns Hopkins University, is also entitled to the 

 thanks of the Institution for assistance in revising proofs dui'ing the 

 period when Professor Yerrill was iU. 



