26 
WILLIAM KEITH BROOKS 
for the reader to follow, and his command of language is admir- 
ably suited to the needs of the naturalist. His technical papers 
always show order and proportion and a fine precision in the use 
of words. These qualities appear too in his one text-book, the 
^'Handbook of Invertebrate Zoology/' a manual so excellent that 
it has been a model for many later books in this field. His popular 
articles and lectures reveal the same logical habit of mind, but 
in these it is the graphic description that especially seizes the mind 
of the reader. Particularly pleasing and effective are the descrip- 
tions of scenes of nature in which animals dominate, or of the be- 
havior of individual animals; In the argumentative portions of 
his later writings dealing with heredity and the philosophical 
aspects of nature, Brooks is not always easy to follow. He leaves 
a good deal of responsibility on the reader. Yet these writings 
contain much that is beautiful in style as well as in idea, much 
that is very quotable, real ^'nuggets of wisdom, products of deep 
thought as well as of careful observation. ''^^ 
Researches on the Tunicata.^^ Brooks' first contributions on 
the Salpidse appeared in 1875- '76. He observed that the eggs, 
which are borne by the individuals of the chain, arise really in 
the solitary Salpa and are passed into the stolon early in its devel- 
opment. Each individual of the chain receives usually one (in 
some species more) of these eggs and serves as nurse to the embryo 
which comes from it. Salpa, therefore, does not show true alter- 
nation of generations, and Chamisso's discovery of an ap- 
parent metagenesis in this form must be looked on as a misin- 
terpretation of the phenomena. In his later study Brooks found 
that the spermatozoa as well as the eggs come from the mass of 
germ cells lying in the ventral part of the solitary Salpa, so that 
the solitary Salpa is in reality a potential bisexual animal. 
Brooks worked out in far greater detail and with greater clear- 
ness than any other student the development of the buds upon the 
stolon, and showed the fundamental harmony of the process of 
" President D. S. Jordan. 
Professor M. M. Metcalf, Oberlin College. 
