WILLIAM KEITH BROOKS — CONKUN 



of the Hydromedusae was a solitary swimming hydra, or actin- 

 ula, with no medusa stage, but probably with power to multiply 

 by budding; (2) this became more highly organized, better 

 litted for swimming life, until it was converted into a medusa, 

 with swimming bell and sense organs, developing directly from 

 the egg, but exhibiting during growth the stages through which 

 the race had passed; (3) after this the larva derived some ad- 

 vantage in becoming attached, either as a parasite or semi- 

 parasite, and in this condition it budded off other larvae, all of 

 which became medusae; (4) the sessile life of the larva was so 

 advantageous that it was perpetuated by natural selection and 

 the primary larva lost its tendency to become a medusa, and 

 remained a sessile hydra, budding off larvae which became 

 medusae; (5) the primary larva acquired power to produce 

 other larvae, which remained permanently in the hydra state ; 

 and (6) finally, the communities thus formed became polymor- 

 phic by division of labor, and the sessile habit became so advan- 

 tageous that the free medusae became degraded into medusa 

 buds on the bodies of the sessile hydras, or on the blastostyles. 

 Following this monograph, he published six shorter papers on 

 Hydromedusae, the last appearing only one year before his 

 death. A monograph on American jelly fishes, which he had 

 worked upon for many years, was never completed, though 

 many of the drawings and descriptions were used in some of 

 the other papers named. 



He wrote but one text-book, his "Handbook of Invertebrate 

 Zoology,'' 1882, but this was so excellent that it has been a 

 model for many subsequent books on that subject, and it is 

 probable that if it had been handled by a larger publishing 

 house its success would have been much greater. He was also 

 the author of many scientific articles of a popular sort, in which 

 kind of writing he showed unusual ability. He was inclined 

 to look upon various human problems, such as the education 

 and political position of woman, from the standpoint of zool- 

 ogy, and his popular discussions of the possible improvement of 

 the human race, of instinct and intelligence, of heredity and 

 variation, etc., were both novel and suggestive. 



His chief interest was always on the philosophical side of 

 biology, and into this he put a large part of his life work. 



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