REPORT OF ASSISTANT DIRECTOR. 49 



cray-fishes, which, is now the second in size and number of species in 

 the United States, being exceeded only by that at the Museum of Com- 

 parative Zoology, Cambridge. It contains forty-six Korth American 

 species. The collection of Echini, which holds the same relative rank, 

 has also been almost completely identified, and other groups are being 

 rapidly worked over. 



In June, the west hall of the Smithsonian building, devoted to the 

 exhibition of marine invertebrates, was opened to the public, and al- 

 though the collections now displayed, fill only the wall cases surround- 

 ing the room, they present a very creditable appearance, and all the 

 groups belonging to this department are represented to a greater or less 

 extent. The dried collections not on exhibition have been mostly trans- 

 ferred to the north-west gallery of the main hall, which will also serve 

 as a general work-room for the department. 



Soon after the middle of June, the curator and his assistants left for 

 Wood's Holl, Mass., to take part in the summer explorations of the U. 

 S. Fish Commission. 



[i) Department of Invertehraie Fossils {Paleosoic). 



Mr. Charles D. Walcott, honorary curator of this department, re- 

 ports that his principal work has consisted in identifying and labeling 

 a collection of Carboniferous fossils which were in the old Smithsonian 

 collection. This work is now well advanced, and will soon be completed 

 as far as identifying the species from the register can be done. In the 

 laboratory the time of the curator has been chiefly devoted to the prep- 

 aration and study of the Cambrian faunas of North America. This 

 has been done in connection with his work for the Geological Survey.* 

 A large number of types and a great quantity of specimens of described 

 species will be adtled to the Museum collections as a result of this work. 

 A number of minor accessions have been received from various persons 

 throughout the country. A large addition was made to the collection 

 in the latter part of 1884, a full discussion of which was presented in 

 the report for that year. Another valuable contribution from the Geo- 

 logical Survey will probably be made in the autumn of the present year. 



{Ic) Department of Invertehraie Fossils {Meso-Genozoic). 



Dr. Charles A. White, the honorary curator of this department, states 

 that a number of important accessions have been received during the 

 first six months of this year, and that some of them constitute new ad- 

 ditions to the collection. Descriptions of these have been published in 

 the various bulletins of the U. S. Geological Survey. The work of pre- 

 paring the collections of the Museum has been in progress, and the in- 

 stallation of types has been commenced. Since the beginning of the 

 year considerable space has been assigned to this department in the 

 gallery of the Smithsonian Institution, and the work of preparing ma- 



* See Bulletin 10, U. S. Geol, Survey. 

 H. Mis. 15, pL 2 1- 



