62 Report of the President 



ened throughout. A work of more scientific importance, and 



one to be at once undertaken, is the revision of the generic 



names — not infrequently perhaps of the specific names also — 



of the exhibited shells. Such changes become imperative, in 



order that the authoritative value of the collection may be 



maintained. 



Six new glass models of distinctive Protozoa have been 



placed on exhibition in the Darwin Hall. Despite many 



^ . tt n difficulties, the elaborate and complicated Tide 

 Darwin Hall ^ , n ' , , r , . 



Pool Group has been brought nearer completion, 



and the novel Bryozoa Group has also been advanced. Both 

 should be on exhibition in the near future. Other new exhib- 

 its, illustrating evolutionary principles, are the Director's 

 panel showing the variation and distribution of Geospiza in the 

 Galapagos Islands, and five panels of the Mendelian exhibit, 

 showing the history of hereditary characters of the seeds 

 and flowers of peas, as well as the inheritance of coat-color 

 and pattern in rats. The material for the last named was 

 presented by Professor William E. Castle and Mr. Raymond 

 L. Ditmars. Models of Tahiti and of the related islands 

 Raiatea and Tahaa have been prepared for installation; they 

 illustrate certain phases of the subsidence-theory of Darwin, 

 and they will also bear shells of the genus Partula showing 

 the variations of the several species and subordinate forms in 

 different geographical localities. 



In the division of insects and spiders, unusual success has 

 been attained. Many new and striking exhibits have been 

 installed which fill out the general scheme estab- 

 Spiders lished some years ago. The problems of the 



study collection are especially difficult on account 

 of the great number of species and because the specimens 

 themselves are so numerous. Yet their general arrangement 

 has now reached a point where some freedom has been gained 

 for the prosecution of researches of a general nature. 



The department as a whole has been greatly strengthened 



by the accessions of the year. In addition to the series of 



Porto Rican invertebrates that have been men- 



tioned as accruing through the work of field 



parties, we have received a collection of annulates (from 



