288 REPORTS ON INVESTIGATIONS AND PROJECTS. 



A study of the ecology of Lepti?wtarsa has been undertaken and 

 the observations and data prepared for publication. The studies 

 along this line indicate clearly that for these animals 'the two great 

 ecological factors are relative humidity and heat. Of these relative 

 humidity (not annual rainfall or precipitation of any kind) is of far 

 greater importance than heat; while light, soil, altitude, etc., are 

 minor factors. It is surprising to find how slight a change of rela- 

 tive humidity, temperature, or light conditions is necessary to inhibit 

 the existence of many of the Lepiinotarsa in all excepting very 

 narrow habitats. 



Yatsu, N., Columbia University, New York, New York. Grant 

 No. 268. Experimental study of the Nemertinc egg. (For first 

 report see Year Book No. 3, p. 144.) $1,000. 



Abstract of Report. — Dr. Yatsu reports that he has carried out 

 under this grant a series of experiments on the egg of Cerebratulus 

 lactcus during the summer of 1905 at the Harpswell Laboratory, 

 South Harpswell, Maine. The rearing of egg fragments from vari- 

 ous regions, effects of mechanical pressure, development of isolated 

 blastomeres, and the like were performed at different stages. He 

 made a careful analysis of the progressive processes of germinal 

 regions from the unsegmented eggs up to the gastrula stage. He 

 also clearly showed that there is a strong rugulatory tendency in 

 the later embryos. The remaining half of his work, i. e., the study 

 of the influence of the chromosomes and cytoplasm on the morpho- 

 genic processes, will be carried on during the coming winter at the 

 Naples Zoological Station. 



Naples Zoological Station, Naples, Italy. Grant No. 253. For 

 maintenance of two tables. (For previous reports see Year Book 

 No. 2, p. cliv, and Year Book No. 3, p. 145.) $1,000. 



Abstract of Report . — As in previous years, the grant was made to 

 aid the laboratory in paying for the maintenance of two research- 

 tables. The persons occupying the tables during the past year were 

 assigned to them and notified of appointment by the director of the 

 laboratory. (Report not yet received.) 



Marine Biological Laboratory, Woods Hole, Mass. Grant No. 252. 



(For previous reports see Year Book No. 2, p. xlv, and Year 



Book No. 3, p. 144.) $10,000. 



Abstract of Report. — As in the two previous years, the grant was 



made to aid the laboratory in paying for the maintenance of twenty 



research tables. The persons assigned to the tables were selected and 



notified of appointment by the director of the laboratory. 



