REPOET ON THE POLYZOA. 
iii 
Classification. 
As to the scheme of classification followed in this Report, and set forth in the sub 
joined Table on pages xxii, xxiii, it is scarcely necessary to remark that it has no pretension 
to be regarded as more than a convenient, and, to a considerable degree, artificial arrange- 
ment, like all others that have been proposed. For although many of the family groups 
may in some measure be regarded as expressing natural alliances, many of them, more 
especially in the Subdivision C.,or Escharina, can only be considered as artificial, and as 
such they must perhaps remain until we are better acquainted with the true significance 
of the minute parts or organs upon which the distinctive characters are in many cases 
founded. Nor at present, perhaps, are we in a position fully to appreciate the relative 
value of the zocecial as compared with the zoarial characters, which of late it appears 
to be the fashion, unduly as I think, to depreciate ; the individuality of the zoarium 
as a continuous whole or entity having been too much overlooked in the almost 
exclusive consideration of its component parts or segments. 
Nevertheless, in order to place myself as far as possible in accord with modern views, 
I have, in the heterogeneous Family Escharid.e more especially, adopted partially the 
nomenclature proposed by Mr. Hincks and Prof. Smitt, but in doing this I have found 
it impossible to avoid a certain amount of the confusion necessarily incidental to an 
attempt to graft a new system upon an old one, based on a different set of characters. 
Geographical and Bathymetrical Distribution. 
With respect to the geographical distribution of the species enumerated in the Report, 
I have thought it convenient to divide the oceans traversed by the Challenger into seven 
regions, distinguished by the letters A, B, C, D, E, F, G ; three being to the north and 
four to the south of the equator, each including 90° of longitude, as shown in the 
accompanying map, in which also are marked the Stations from which any Polyzoa were 
obtained. 
A. North Atlantic Region, between the parallels of 70° W. and 20° E. 1 
B. South Atlantic Region, from 70° W. to 20° E. 
C. South Indian or Kerguelen Region, from 20° to 110° E. 
D. Australian Region, from 110° E. to 160° W. and S. 
E. Philippine or Japanese Region, from 110° E. to 160° W. and N. 
F. North Pacific Region, from 160° W. to the west coast of North America. 
G. South Pacific, from 160° to 70° W. 
In the following List the Stations in each geographical region are arranged in 
bathymetrical order, beginning with those of the greatest depth. To the names of the 
1 One Station, viz., 44, is 71° 40' W. 
