342 The Smithsonian Institution 



assembled, consisting chiefly of the great series formed by the 

 United States Fish Commission, supplemented by the collec- 

 tions of many American naturalists. The collection of Alas- 

 kan fishes is very large, and is not extensively duplicated 

 elsewhere. 



The series of fishes collected in connection with the Pacific 

 Railroad Surveys and the first Mexican Boundary Survey 

 are of special importance as containing the types of a large 

 proportion of the species of the middle and western United 

 States. They have been supplemented in recent years by 

 important series collected under the auspices of the Fish 

 Commission and by private collectors. 



The Department contains also many single specimens of 

 great value, which have been made the basis of new families 

 and genera. 



Regarding the Department of Mollusks, Mr. William H. 

 Dall, the Honorary Curator, writes as follows : 



" The collection of mollusks was founded primarily upon 

 the specimens gathered by the United States Exploring Ex- 

 pedition under Wilkes during 1838-42, which formed the 

 types of the folio volume on the mollusks and shells by Doc- 

 tor A. A. Gould, included in the series of United States 

 Exploring Expedition reports published by Congress. To 

 these were added the types of the mollusks of the North 

 Pacific Exploring Expedition under Ringgold and Rodgers, 

 collected by Doctor William Stimpson, and described by 

 Gould. The collections were very rich and valuable, for the 

 time, but underwent serious vicissitudes before and after be- 

 ing received by the Smithsonian Institution previous to the 

 organization of the museum, so that the series as it now 

 exists is by no means complete. Nevertheless these shells 

 form an interesting and important portion of the collection. 



" Next in point of number and value comes the collection, 



