106 Experimental Evolution, Variation, and Heredity 



No. 259. (Paper No. 29, Station for Experimental Evolution.) 

 DAVENPORT, CHARLES B., and MARY F. SCUDDER. Naval Officers: Their Heredity 



and Development. Octavo, iv-|-236 pages, 60 charts. Published 1919. 



Price $3.00. 



This is a study of the family and personal history of 68 naval officers. It has 

 been made with the aim of learning if there is any characteristic set of juvenile 

 reactions that is diagnostic of high success in the vocation of naval officer. Also, 

 if any light can be thrown by family history upon the probability that a given boy 

 has received hereditary traits essential to success as a naval leader. Successful 

 naval officers are of various types, such as fighters, strategists, administrators, 

 explorers, and adventurers. One part of the study relates to the kind of tempera- 

 ment required for success in each type of officer and the ways in which it is shown 

 in youth. A special study is made of the inheritance of sea-lust, hyperkinesis in 

 fighters and nomadism in naval men. The initial inquiries receive a positive answer. 



No. 265. (Paper No. 30, Station for Experimental Evolution.) 

 LAUGHLIN, HARRY H. The Duration of the Several Mitotic Stages in the 

 Dividing Root-Tip Cells of the Common Onion. Octavo, 48 pages, 8 

 charts. Published 1919. Price $1.50. 



The ultimate object of this study is to aid in the analysis of the dynamics of 

 mitosis as exemplified in the onion (Allium cepa). In this direction it accomplishes 

 two steps. First, it devises and proves an accurate method for measuring the relative 

 and absolute average durations of the several mitotic stages in cell-division. Second, 

 it makes use of this method in determining such durations for each of the ten 

 arbitrarily marked stages in the mitotic cycle of the dividing cells of the root-tip 

 of the onion, at three temperatures, 10C., 20C, and 30C. The method followed 

 is a statistical one, based upon stage-counts and their classification. The validity 

 of the method is proven by means satisfying both the mathematical and cytological 

 aspects of the problem. 57,000 cell-counts, distributed over 11 mitotic stages and 

 through 19 observation-instants, were made. The Qi > value for each of the ten 

 stages for the temperature-differences 10C. to 20C. and 20C. to 30C. are cal- 

 culated. These values vary from 1.1701 to +4.9463. Each arbitrarily marked 

 mitotic stage presents a characteristic temperature-reaction, thus indicating a unique 

 complex of physical and chemical forces active in each stage of mitotic progress. 



No. 295. (Paper No. 31, Station for Experimental Evolution.) 



MOHR, O. L.. and CHR. WRIEDT. A Neiat Type of Hereditary Brachyphalangy in 

 Man. Octavo, 64 pages, 7 plates, 4 text figures. Published 1919. 

 Price $1.00. 



A study of an inherited shortness of the second phalanx of the index finger 

 and corresponding toe, that occurs in a Norwegian family. The peculiarity is 

 inherited as a Mendelian dominant. It is traced through six successive genera- 

 tions of affected individuals, beginning in 1764. Photographs of individuals be- 

 longing to five generations are given, and radiographs of members of four 

 generations. Measurements and tables showing the correlation between the 

 length of the affected phalanx and that of the second phalanx of the ring finger 

 are presented, both for abnormal and for normal hands. These show that there 

 are two distinct types of brachyphalangous individuals, in one of which the af- 

 fected joint is much shorter than in the other. Both types are due to the same 

 dominant gene; the difference between them is probably due to modifying genes. 

 There is one individual in the pedigree that was perhaps homozygous for the 

 brachyphalangy gene. This individual was very abnormal in her "whole osseous 

 system," and died in infancy. 



No. 25. GULICK, J. T. Evolution Racial and Habitudinal. Octavo, xii+269 pages, 

 5 plates. Published 1905. Price $1.00. 



Gives many facts concerning divergence of varieties and species distributed in 

 more or less isolated districts, presents an analysis of the factors of both racial and 

 habitudinal evolution, and shows that there is constant interaction between these 

 classes of factors, and also between the autonomic and the heteronomic factors 



