REVIEWS. 
On the Development and Fat-corpuscles of the Marine Polyzoa. 
By F. A. Smirr. (Om Hafs-Bryozoernas utveckling och 
fettkroppar.) Stockholm, 1865. 6 plates. 
Unper the above title we have to welcome the appearance 
of an extremely interesting communication on the subject of 
the development and several points in the life-history of the 
Polyzoa, or as the author terms them the marine Bryozoa. 
Unfortunately this essay is written in one of the almost 
unknown tongues, and we have consequently found so much 
difficulty in its perusal as to be at present prevented giving 
such a full abstract of its contents as we could have wished, 
and hope to be enabled to afford, with some assistance as to the 
language, at a future opportunity. On this occasion we will 
content ourselves with giving a summary of the contents of 
a former, as it would seem preliminary paper, on the same 
subject, which was published as an Inaugural Dissertation at 
Upsala in the year 1863, under the title of “ Bidrag till 
Kannedomen hafs-Bryozoernas utveckling.”’ 
For the following summary of the chief points noticed by 
M. Smitt in this Dissertation we are indebted to Professor 
Leuckart’s Report on the Natural History of the Lower 
Animals for the year 1863—just received. 
In the Bryozoa the author distinguishes six different forms 
of cells, viz.:—animal-cells, ovicells, avicularia, vibracula, 
radical fibres, and stem-cells ; but all of these, it should be 
stated, are never found existing together. In the Cyclosto- 
mata the animal-cells are found either alone or in conjunc- 
tion with ovicells (Crisia) ; in the Ctenostomata, these cells 
are often met with conjoined with radical fibres (Vesicularia) 
into a common stem, whose cells contain the colonial nervous 
system, which has repeatedly formed the subject of the 
author’s observation; and amongst the Cheilostomata are 
found species, as Cellularia, which exhibit a still greater 
