146 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 
THE NUMBER OF SPECIES 
As here identified, the present record contains 472 valid species 
(plus 1 copepodid larva of Pennella), of which 29 are new to science. 
Such a large number of species would naturally be expected when 
the size of the Albatross collections is taken into consideration. When 
the number of tow-nettings runs into the thousands the number of 
species might well reach into the hundreds. A few parasitic species 
have been included because when captured they were swimming freely 
and formed as integral a part of the plankton as any of the other 
species. In addition, the Albatross during the voyages here recorded 
obtained many other parasitic species taken from their respective 
hosts. These have been fully described and figured in papers dealing 
with the parasitic copepods that have appeared under the author’s 
name in the Proceedings of the United States National Museum. 
NETS AND METHODS OF COLLECTING 
Various sizes of nets were used in collecting the Albatross plankton. 
The commonly used surface tow nets of the earlier days of the Alba- 
tross were rigged on rings 12 to 18 inches in diameter, but larger 
nets with rings from 4 to 514 feet in diameter were aiso frequently 
employed. From 1891 through 1895, and more rarely in later years, 
intermediate tows were usually accomplished with closing nets of two 
types—the Tanner net of about 214 feet in diameter, and the Townsend 
net of 3 feet in diameter. Beginning with 1904 the smaller tow nets 
were Kofoid nets of three styles rigged on rings ranging from 12 
inches to 2 feet in diameter. These were used separately, at times in 
tandem or series, and occasionally in conjunction with larger open 
surface and vertical nets of four different styles. The intermediate 
nets of these days were, almost without exception, of the open type 
and of two sizes, 4 and 514 feet in diameter. During the Philippine 
cruise, 1907-10, six styles of Kofoid nets were used. All six were 
suspended from 14-inch rings, the standard of that time. There were 
also three styles of open intermediate nets with rings either 514 or 10 
feet in diameter, as well as an open plankton net fastened to a 2-foot 
ring. 
Surface tows were drawn horizontally immediately, or a little, 
below the surface for varying times and distances. Less often were 
vertical hauls made from various depths to the surface. More rarely 
were plankton nets drawn horizontally at a given distance below the 
surface and then diagonally to the surface. Except in the early days, 
when one or ancther type of closing net was used, the horizontal tows 
became virtually a combination horizontal-vertical haul which, how- 
