210 



SCIENCE 



[N. S. Vol. XXXVIII. No. 972 



Commissiou Station at Woods Hole. In 

 the summer of 1896 he worked for a while 

 at the marine laboratory of the University 

 of Pennsylvania at Sea Isle City, N. J. 

 The summer of 1897 he spent at the Marine 

 Biological Laboratory, Woods Hole, and 

 thereafter nearly every summer of his life 

 Avas spent there, except for four summers, 

 when he was in Texas. 



In 1897 he was appointed lecturer in 

 zoology at the University of Pennsylvania ; 

 in 1898 he was advanced to an instructor- 

 ship and in 1900 to an assistant professor- 

 ship. During the years 1898 to 1903 he 

 was also professor of biology and director of 

 the museum in the Wagner Free Institute 

 of Science in Philadelphia. In 1903 he 

 was called to the professorship of zoology 

 in the University of Texas, where he re- 

 mained until 1908, when he became pro- 

 fessor of zoology and head of that depart- 

 ment at the University of Pennsylvania, 

 and in this position he continued until his 

 death in 1912. 



He was a trustee of the Marine Biolog- 

 ical Laboratory and clerk of the corpora- 

 tion of that institution from 1908 until his 

 death, and during the same period he was 

 co-editor of the Journal of Morphology. 

 He was a member of the American Asso- 

 ciation for the Advancement of Science, 

 the American Society of Naturalists, the 

 American Society of Zoologists, of which 

 he was president in 1910, the American 

 Philosophical Society, the Academy of Nat- 

 ural Sciences of Philadelphia and the Texas 

 Academy of Sciences, of which he was 

 president in 1905. 



This bare catalogue of the positions of 

 responsibility and honor which he held in- 

 dicates how rapidly he rose to prominence 

 in his science, but it does not indicate the 

 means by which he achieved distinction. 

 It remains to describe his unusual qualities 

 as an investigator, as a teacher and organ- 

 izer, and as a man. 



He was an unusually active investigator 

 in many fields, and a ready and prolific 

 writer. His life as an author extended 

 only from 1894 to 1912, eighteen years in 

 all, but in that time he made many valuable 

 contributions to science and published one 

 large book and more than eighty papers. 

 His breadth of view and of sympathy is 

 indicated by the numerous branches of 

 zoology to which he contributed. Sixteen 

 of his papers were devoted primarily to 

 taxonomy, five to distribution, eleven to 

 ecology and behavior, sixteen to morphol- 

 ogy, twenty-five to cytology, eight to phy- 

 logeny and one to experiment. He had 

 just begun on experimental work during 

 his last year, and there is no doubt that he 

 would have contributed largely to this 

 branch of zoology had he lived. His 

 breadth of view is shown also if one con- 

 siders the groups of animals studied. His 

 earliest publications dealt with nemertean 

 worms, on which he wrote ten papers; his 

 observations on birds are given in five 

 papers, and those on other vertebrates in 

 two; he published ten papers on hair- 

 worms, two on rotifers, fourteen on spi- 

 ders, three on insects, twenty-five on cytol- 

 ogy, of which fifteen dealt with insects 

 alone, and sixteen on phylogeny and gen- 

 eral topics (see bibliography). 



Most of this work was very good and 

 som.e of it was remarkable for its influence. 

 Among his most important contributions 

 must be mentioned particularly his various 

 papers on the habits of spiders (Nos. 31, 

 37, 38, 41, 42) ; his studies on the nucleolus 

 (Nos. 47, 48, 50) ; and his extensive studies 

 on spermatogenesis (Nos. 49, 51-71). In 

 the latter field a discovery of really epoch- 

 making importance was his observation of 

 the conjugation of separate chromosomes 

 in preparation for the maturation divi- 

 sions, and his clearly reasoned conclusion 

 that one chromosome of each pair is of 

 paternal and the other of maternal origin. 



