280 THE AMERICAN NATURALIST. [VoL. XXXII. 
that he is passing away. Books built on lines like those which Dr. 
Shufeldt follows will tend to render the time of his total extermina- 
tion far distant, and, in case a second edition of this work is called 
for, we hope that it will be developed largely on the model shown in 
the chapter on bats, to our mind the best chapter in the whole work. 
It would be well in a second edition to omit the final chapter on 
museums, which, as it now stands, has no vazson d’être. 
Origin of the Cleavage Centrosomes. — Boveri, in 1887, was the 
first to prove that the centrosome which gives rise to the centrosomes 
of the first cleavage spindle is brought into the egg by the spermato- 
zoon. This observation, made on the egg of Ascaris, led to the 
formulation of the following conclusion by Boveri: “The ripe egg 
possesses all of the organs and qualities necessary for division except- 
ing the centrosome, by which division is initiated. The spermato- 
zoon, on the other hand, is provided with a centrosome, but lacks 
the substance in which this organ of division may exert its activity. 
Through the union of the two cells in fertilization all of the essential 
organs necessary for division are brought together; the egg now 
contains a centrosome which by its own division leads the way in 
the embryonic development.” ! 
Additional evidence was soon furnished by Vejdovsky, who, in the 
case of Rhynchelmis, followed the disappearance of the egg centro- 
some, a thing which Boveri had not actually done. Fol, however, 
in 1891, described the remarkable process in the echinoderm egg, 
which he called the “Quadrille of Centers,” and maintained that 
the egg centrosome and sperm centrosome divide, each into two, the 
daughter centrosomes then conjugating, a maternal with a paternal 
one, to form the two centrosomes of the first cleavage spindle. His 
paper was generally accepted, in spite of the earlier work on the 
subject, and was confirmed by the results of Guignard, Conklin, 
Blanc, Van der Stricht, and Schaffner. Belief in the existence of 
the “quadrille” was destined to be dissipated in the light of later 
research, and a score of investigators have definitely proved its 
mythical character; among these may be mentioned Fick, Wilson 
and Mathews, Mead, Boveri, Hill, Riickert, Reinke, Kostanecki and 
Wierzejski, Sobotta, and several others. A return has, therefore, 
been made to Boveri’s original contention that the cleavage centro- 
somes are derived solely from the sperm centrosome, and, as the 
1 The Cell in Development and Inheritance. By E. B. Wilson. New York, 1896, 
pp- 141, 142. 
