Report of the President 5 1 



trate, with living material, several features of general interest 

 which cannot well be shown in casts or preparations: among 

 these are sexual differences (colors), breeding habits (nesting 

 or viviparity), variation under domestication, — features ex- 

 plained by descriptive labels accompanying the jars. 



In this connection we should mention the annual meeting 

 and exhibition of the Aquarium Society, which was held in the 

 Museum, under the auspices of the department. This was 

 largely attended, and its contributors deserve great praise for 

 the interest and importance of their exhibits. Many tropical 

 fishes were shown which apparently had never before been 

 brought living to America. 



EXISTING INVERTEBRATES— DARWIN HALL 



Henry Edward Crampton, Curator 



Department of Invertebrate Zoology. — The scientific 

 staff has been increased by the addition of Mr. Charles W. 

 Leng, as Honorary Curator of Coleoptera. In the distribution 

 of duties and in other routine respects the departmental organ- 

 ization remains the same. 



The most noteworthy feature of departmental progress 

 during the past year has been the increased development of 

 field and exploration work. No fewer than seven expeditions 

 have been sent out for longer or shorter intervals, and their 

 work has been coordinated through its relation to the larger 

 tasks which the department has set for itself, namely, the 

 study of the distribution, evolution and migration of the faunas 

 of North and South America. As these continents form the 

 most natural territory for field studies in invertebrate zoology, 

 plans have been formulated for work to extend over ten years 

 at least upon the problems specified. Particular attention 

 must be directed to the changes which took place after the 

 close of the Glacial Period, by which the North American 

 fauna then existing was amplified by immigration from South 

 America. Further knowledge of the former continent is no 

 less essential than discoveries of new forms in the latter area. 



