66 Report of the President 



magnified to scale. Seven species of the latter will be repre- 

 sented, while among the associated forms certain hydroids 

 budding forth medusae will exemplify alternation of genera- 

 tions. The complete life history of a typical colonial ascidian 

 (Botryllus) will also be shown from the free- swimming larva 

 to the stationary adult animal. This group presents many new 

 problems of preparation and installation, and will be an effec- 

 tive contrast to the other window groups in the Darwin Hall. 

 The final panel for the Mendelian exhibit has been practically 

 completed and is now ready for installation. It represents one 

 of the simplest cases of Mendelian color inheritance as shown 

 in the Four o'Clocks (Mirabilis jalapa). The series of Proto- 

 zoa models has been amplified by several striking items, notably 

 models of the remarkable Radiolarians, Collozoum inerme, 

 Trypanosphcera transformata and Lithocircus arborescens. A 

 chart illustrating the phylogeny of invertebrates and their rela- 

 tion to the vertebrate stock has been prepared and temporarily 

 installed in the Synoptic Hall of Mammals. When completed 

 this chart will illustrate, by means of specimens and models, 

 the chief types of the animal kingdom, as well as their phy- 

 logeny. In addition, a series of the flat worm and round worm 

 models, purchased for the Museum in Japan by Major Bash- 

 ford Dean, have been remounted and placed on exhibition. 

 Two items have also been added to the series of nudibranch 

 models. Throughout the year the work of enlarging and re- 

 fitting the exhibition cases has continued, and five cases are 

 now completed. During 19 18, 9,728 pupils visited the Darwin 

 hall in 361 classes from 172 different institutions. Each class 

 was accompanied by its teacher and came for the purpose of 

 studying definite exhibits. Of the institutions represented, 47 

 are from out of town, 104 are public schools, 46 private schools, 

 and 15 parochial schools. Seven of the number are collegiate 

 institutions. 



The cataloguing and arrangement of our general collection 

 of Brachyura, begun in 1917 by Dr. W. G. Van Name, were 

 completed by him during the early months of this year, and 

 since then a general rearrangement of the catalogued material 

 and uncatalogued accessions of the invertebrate collections has 



