NOTICES OF NEW BOOKS. 311 
that, most unsatisfactory and unscientific as this classification is 
now seen to be, Busk’s descriptions were extremely clear; and 
these have enabled specialists to use them as indices and 
become acquainted with their characters, and thus collect material 
for a more natural classification. 
Some time after the publication of Busk’s works, Smitt intro- 
duced a new ciassification, based mostly on the form of the 
zocecium, and using largely the shape of the oral aperture. This 
was applied to the northern Bryozoa, and also to those from 
Florida, and a new era was inaugurated ; but the difficulties of 
the subject are so great, that in many cases the too rigid carrying 
out of his plan gives unsatisfactory results. But any classification 
must comprehend much of Smitt’s, and we now have one modified 
by My. Hincks, or rather, we should Say, we Now see it carried out, 
and can better judge how it will work than we could from the 
preliminary notices which had already appeared in the ‘Annals,’ 
Of course most that is objectionable in the British Museum 
Catalogue is discarded, and the characters used are for the most 
part those employed by Smitt, the main difference being that 
Mr. Hinecks makes much more use of the secondary aperture 
than had been done before; but in our opinion it seems probable 
that some modification may be required in some of the genera 
almost entirely based on the nature of the peristome ; but should 
it be found in a few cases that this has only served as a means of 
cataloguing material, and is thus again a stepping-stone to further 
advances, it should not be forgotten that improved classification 
advances the science, and it may be many years before the addition 
of fresh material may render fresh changes necessary. 
This is not the place for a critical examination of all the new 
or modified genera with which we have expressed general approval, 
but we must express regret that a genus which has been shifted 
about as much so Cellularia, and which might therefore be 
discarded altogether, has been retained (though in quite a different 
sense from that intended by Smitt, who employs it in a wider 
sense), and contains a large number of the genera included by 
Pallas (who created the genus), whereas, as Mr. Hincks points 
out, it does not, as now limited by Busk, include any of the forms 
placed by Pallas in the genus. 
There are interesting chapters on the avicularia or “birds’- 
head processes”; on the reproduction and the affinities of the 
