ZOOLOGY — CASTLE, CRAMPTOX, NAPLES ZOOLOGICAL STATION. 24I 



In the selection experiments with rats, in which also I have been assisted 

 by Dr. Phillips, continuous and progressive modifications are being secured 

 of a color-pattern which behaves as a simple unit-character, mendelizing in 

 crosses. The modifications, which are quantitative, are being obtained in 

 opposite directions, plus and minus, in two distinct series of experiments, 

 and there is reason to regard these modifications as permanent in nature. 

 This conclusion supports the idea which I have presented in publications Nos. 

 23, 49, and 70, that mendelian unit-characters are not simple and unchange- 

 able, like chemical atoms, but that they are subject to quantitative variation, 

 so that by selection from among the variates new races may be gradually 

 but surely evolved. The efficacy of selection in evolution was firmly main- 

 tained by Darwin, but has in the last decade been seriously called in question, 

 many investigators having reached the conclusion that mutation is the only 

 important agency in the production of new races. Our own studies, how- 

 ever, strongly support Darwin's view, that new races may arise in two dis- 

 tinct ways, (i) by cumulative selection of slight variations, and (2) by 

 sports (or mutations). 



Three other investigations, which have been in progress for some time, 

 will probably be sufficiently advanced for publication within the next year. 

 They relate to (i) the inheritance of color in mice (upon which subject two 

 preliminary publications have been made this year) ; (2) the results of hy- 

 bridizing Cavia aperea with the guinea-pig; and (3) blending inheritance in 

 rabbits. 



Crampton, H. E., Columbia University, New York, New York. Grant No. 



563. Study of variation, heredity, and geographical distribution of 



Polynesian species of Par tula. (For previous reports see Year Books 



Nos. 6-9.) $2,500 



The work of classifying and measuring the snails is progressing, so that 



the final statistical results can be established. The first section of the report, 



dealing with certain species from Tahiti, is practically completed. 



Naples Zoological Station, Naples, Italy. Grant No. 686, Maintenance of 

 tzuo tables for American biologists. (For previous reports see Year 

 Books Nos. 2-9.) $1,000 



During the last term the two Tables of the Carnegie Institution were made 

 use of by : 



Dr. O. Riddle, instructor in experimental zoology at the University of 

 Chicago, from September 26, 1910, to March 3, 1911, and Prof. Dr. F. D. 

 Lambert, botanist, of Tufts College, ^Massachusetts, from March 5 to August 

 10, 1911. 



Both scientists have been eagerly working in the Laboratories, Dr. Riddle 

 particularly on the formation of melanine in various animals, and Dr. Lam- 

 bert (who was assisted by Mrs. Lambert) on the fructification of algae. 



16 — YB 



