82 re;ports on investigations and projects. 



cELi. studies in heredity. 



Miss Lutz continued the study of the somatic chromosomes of the Oeno- 

 theras and their hybrids begun four years ago and carried on ever since with 

 great industry, over 4,300 fixations having been prepared for microscopical 

 study ; in the best-studied hybrids photographs have been made of type and 

 exceptional forms to illustrate distinctive characters of early and late rosette 

 stages, young and adult flowering plant, bud, flower, leaf, and fruit ; in all 

 about 350 plates. 



Of the 14 or more topics upon which some data have been obtained the 

 5 following are nearing completion and will, it is hoped, be finished during 

 the coming winter : 



1. Chromosomal history of the Fj offspring of Oenothera lata X O. gigas. 



2. The F2 offspring of Oenothera lata X O. gigas. 



3. The chromosomes of mutants. 



4. Pollen of the Oenotheras and its relation to mutation. 



5. Sex chromosomes of Lychnis. 



STUDIES ON adjustment TO CAVE LIFE. 



During the winter a concrete cave was built, as described in detail under 

 "construction," and a dark-room was fitted up with apparatus for the study 

 of the reactions of organisms to light. The purpose of the cave studies is to 

 learn the way in which body pigment is lost, eyes degenerate or disappear, 

 and tactile organs hypertrophy in animals inhabiting caves, abysmal waters, 

 and other dark situations. 



Dr. A. M. Banta assumed charge of this work about November i, 1909, 

 and since that time has been busy collecting cave animals and installing and 

 maintaining them in daylight as well as in darkness. Closely related species 

 that ordinarily live in the light are being reared in the dark. A necessary, 

 though laborious, part of the work has been acquiring the technique of main- 

 taining the animals. Each species presents a problem in itself, and many of 

 these problems have been solved. The artificial cave affords conditions ap- 

 proximating those of a natural cavern, with the advantages of constant 

 accessibility and of convenience for caring for the organisms. 



The following are now breeding within the cave : 



Asellus communis. Porcellio rathkei. 



Eucrangonyx gracilis (surface form). Copepoda. 



Oniscus asellus. Drosophila. 



Armadillidium vulgare. Tenebrio. 



Porcellio scaber. Silvanus. 



The following animals are being kept in the cave for the purpose of 



breeding : 



Guinea-pigs. Myriapoda. 



Goldfish. ^ Thysanura. 



Sunfish (Lepomisgibbosus). Ceuthophilus. 

 Crayfish (Cambarusbartoni). 



In addition, larvae of 4 species of amphibians are being reared in the cave. 



The following cave forms are being kept in daylight : 



Cambarus pelucidus. Sinella cavernarum. 



Csecidotea stygia. Rhagidia cavicola. 



Eucrangonyx gracilis. 



