56 Report of the President 



will be placed a series showing briefly the classification of 

 molluscs; second, in the eight table cases at the north and 

 south ends of the hall the collections of land shells; third, in 

 the upright railing cases the bivalves or molluscs which have 

 two shells like the common clam; fourth, in the metallic cases 

 the univalves, molluscs which have only one valve or shell like 

 the snails; fifth, special exhibits of shells in the north wall 

 cases. Other cases will contain exhibits illustrating the anat- 

 omy and habits of molluscs; colored transparencies will show 

 them in their habitats. 



Particular emphasis must be put upon the importance and 

 necessity of a systematic study collection, separate from the 

 exhibition series. Great numbers of small forms, abyssal 

 types, and rare obscure varieties are already in hand and 

 others will undoubtedly come to the department; these can 

 never be introduced successfully into the exhibition series. 

 Separate provision in the shape of reserved cabinets must 

 be provided for the security and study of special collections, 

 such as shells secured by an expedition to Lower California, 

 those obtained from the Fish Commission, and from depart- 

 mental expeditions in the Antilles and South America, as well 

 as through exchanges. 



Owing to the urgent demands upon his time made by the 

 transfer and care of the shell collections, Mr. Gratacap has 

 necessarily postponed his projected visit to Porto Rico for 

 the collection and study of the molluscan fauna of that island. 

 It is hoped and expected that this deferred expedition will be 

 made at an early date. 



GEOLOGY AND EXTINCT INVERTEBRATES 



Edmund Otis Hovey, Curator 



Department of Geology and Invertebrate Palaeon- 

 tology. — The growth of this department has continued along 

 some lines of general and economic geology as well as of 

 invertebrate palaeontology. 



Mention of only a few of the more important accessions 

 can be made. Mr. Albert Operti, the artist, presented a 

 series of twenty-two oil sketches made by him on the Peary 



