Vol. X] EVERMANN— DIRECTOR'S REPORT FOR 1920 143 



Department of Invertebrate Paleontology 



The regular work of the Department of Invertebrate Paleontology is 

 considerably varied in character because of the assembling therein of all 

 the collections of fossil animals and plants, as well as those of the shells 

 of living mollusks, and corals and the minerals, which belong to the Acad- 

 emy. While each group must necessarily receive a certain amount of care 

 in order to make the collections readily accessible for study, the greatest 

 attention of the personnel of the Department has been given to the living 

 and fossil mollusks, particularly the latter. The vast Tertiary deposits of 

 these organisms in California have attracted the attention of members 

 of the Academy's staflf since the organization of the institution. Although 

 the valuable collections obtained prior to 1906 were destroyed in the fire, 

 the activities of my predecessors and friends of the Academy have resulted 

 in the building up of one of the largest West Coast series in existence. 

 In the careful selection of the specimens and their orderly arrangement 

 the collection is second to none. 



The study of the fossil shells necessitates having related living forms 

 for comparison, and generous friends have presented material from time 

 to time, so that a very large and valuable working series of recent shells 

 has been obtained. So far as West Coast material is concerned, the 

 Academy's collection probably ranks third in importance at the present 

 time. 



Some specimens of fossil vertebrate animals are also contained in the 

 collections, but throughout its history the Academy has preferred to leave 

 this branch of the work to other institutions. This likewise has been true 

 with regards to the fossil plants and the minerals. 



Such varied and extensive collections require attention along the follow- 

 ing lines: (1) The collection of additional material in the most important 

 groups (field work) ; (2) The proper accessioning, cataloging, and classify- 

 ing of the specimens; (3) The preparation and publishing of reports upon 

 the collections for the use of the members of the Academy and others 

 interested in this branch of science. 



Three important field trips were made by the curator during the period 

 covered by this report. Ten days in April were spent in San Benito 

 County, California, in company with Mr. Joseph Mailliard, Curator of the 

 Department of Ornithology. The collections of land and freshwater mol- 

 lusks secured filled important gaps in our series. Search for fossils in 

 the region proved unsuccessful. 



The United States Bureau of Fisheries requested the services of the 

 curator during the summer of 1920 to take the census of Alaska fur seals 

 on the Pribilof Islands, a task to which he had been detailed annually since 

 1913. After careful consideration of the benefits which the Academy would 

 derive from such a trip, it was decided best to accede to the wishes of the 

 Bureau. The curator, therefore, took his departure on May 27, and, 

 after an absence of about four months, returned on October 1. About 

 one month of this time was occupied with actual fur-seal work, and the 

 remaining available time was devoted to making collections in the branches 



