78 MUSEUM OF COMPARATIVE ZOOLOGY. [Feb. 



To the collection of Mollusks, ten thousand specimens have been 

 added, about one half of which are preserved in alcohol, comprising 

 about one thousand species. 



To the collection of Echinoderms, nine hundred and fifty specimens, 

 representing one hundred and fifteen species, have been added, most 

 of which are preserved in alcohol. The most interesting of these are 

 from Zanzibar, sent by Mr. Webb, Captain Webb, and Captain Millet ; 

 from the Society Islands, sent by Mr. Garret ; from California, sent by 

 T. G. Cary, Esq. ; from Fayal, sent by Mr. and Miss Dabney ; and a 

 large number of original specimens, sent by Professor Valenciennes of 

 the Jardin des Plantes. 



To the collection of Acalephs, seventy-two species have been added, 

 and a large number of original specimens of Morals, described by Pro- 

 fessor Dana, and presented by the Smithsonian Institution. 



More detailed lists of these additions are annexed to this Report, in 

 which the number of specimens obtained from all the donors who have 

 liberally contributed to the increase of our Museum is enumerated. 

 [These lists are omitted here.] 



During the past year, much has also been done respecting the ar- 

 rangement of the collections, and as I have already given an account 

 of the general plan of the Museum in a former Report, I propose now 

 to lay before you the plan of the arrangement of that part of the col- 

 lection which is nearly completed. I deem it the more important to 

 explain it fully, as my experience with other museums has satisfied me 

 that collections of Natural History are less useful for study, in pro- 

 portion as they are more extensive. 



This may seem paradoxical, yet it is undoubtedly true ; for while 

 the most extensive collections answer admirably the purposes of pro- 

 fessional naturalists for special researches and original investigations 

 they are generally beyond the grasp of less advanced students, and 

 cease to be instructive at all for the largest number of visitors of such 

 establishments. In arranging our collections, which are intended at 

 the same time to be instructive for the million and to afford the 

 amplest material for any kind of scientific investigations, it has been 

 my aim to combine these two objects ; and as nothing of the kind has 

 yet been attempted in any large museum, as far as I know, a detailed 

 account of the plan, as adopted in our Museum, may be welcome to 



