^JolSJjaSrfiSr PROaRESS OF MICROSCOPICAL SCIENCE. 47 
we would call attention is Professor Owen's advocacy of the view 
that the white-blood globules divide into red ones (so at least we 
gather from his account). This, our readers will be aware, is a 
different opinion from that of Mr. Wharton Jones, who regards the 
nucleus of the white corpuscle as the future red globule. There 
is a great deal of interesting matter in Professor Owen's volume, 
and the illustrations are numerous and good. 
Ohservations on the Polyzoa : Suh-order Phyladolcemata ; with nine 
plates, by Alpheus Hjatt, Salem, U. S., 1868. The Essex Insti- 
tute is one of the mrst active and useful of the American scien- 
tific institutions, and of the many good memoirs it has furnished 
us with, this is by no means the least either in interest or value. 
Mr. Hyatt is not only an indefatigable observer himself, but he 
is also a careful student of the writings of those who have gone 
before him in this special path of research, and his general " intro- 
duction " on the anatomical structure of the group whose history 
he has written, will be found useful by those interested in 
Polyzoa. The works of AUman, Van Beneden, Leidy, Busk, 
Hancock, De Blainville, Dumortier, and Ehrenberg, have been 
frequently referred to. Professor AUman's work seems to have 
supplied the author with most of his facts, especially those in 
relation to general development and the development of the stato- 
blasts. The chapter on the composition of the endocyst seems to 
us to contain more original matter than any of the others, and 
embraces a statement of the results of the author opposed to those 
of Professor AUman. The plates, nine in number, are very pretty, 
being drawn in white lines in black background, but they appear 
to us to be generalized from many specimens, and to be in great 
measure schematic representations. In most instances they are 
original, and they include species of Fredericella, Plumatella, 
Pectinatella, Cristatella, and Urnatella. Mr. Hyatt's work is one 
which those engaged in the study of Polyzoa should read and 
pass judgment on for themselves. 
PEOGRESS OF MICROSCOPICAL SCIENCE. 
Observations on the Development of the Bony Fishes. — In the last 
number of Max Schultze's ' Archiv fur Mikroscopische Anatomic,' 
Professor Kupffer, of Kiel, has a paper on this subject, in which he 
states that he subjected to microscopic examination the ova of several 
species of fish— the pike, stickle-back, &c., all of them after fecunda- 
tion. The results of his investigations agree in most points with 
those published more than ten years ago by Lereboullet. Some phe- 
nomena, however, in the development of the fecundated ova have been 
more accurately observed and described, and the nomenclature has 
been accordingly slightly altered. Besides the segmentation-cells, 
