6 PROCEEDINGS OF THE NATIONAL MUSEUM VOL, 125 
Gnathiidea, and Phreaticoidea—the first parasitic on other Crustacea, 
the second ectoparasitic in the larval stage on fish, and the third 
found only in freshwater in Australia and South Africa. 
The seven isopod families are represented unequally, both in num- 
bers of species and in occurrences (table 2). To the total of 26 species, 
the Sphaeromatidae and Idoteidae contributed eight each, the 
Janiridae four, the Jaeropsidae and Anthuridae two each, and the 
Cirolanidae and Excorallanidae one each. The inequality is even 
more evident when the frequency of occurrence is considered with 
sphaeromids being found on 45 buoys, idoteids on 48, janirids on 13, 
jaeropsids on five, anthurids only on two, and cirolanids and excoral- 
lanids on one each. 
The Tanaidacea are represented by only three species belonging to 
three genera and two families, Paratanaidae and Tanaidae. The one 
paratanaid species, the cosmopolitan Leptochelia dubia, was found on 
the Atlantic coast side; the two tanaids were taken on the Pacific 
coast. 
The 29 species in the buoy collection were divided almost evenly 
by the continent—13 isopod species and one tanaidacean taken on 
the Atlantic side only (including the Gulf coast and the Bahamas), 
and 13 isopod species and two tanaidaceans taken only on the Pacific 
side (including one species found only in Hawaii). No species was 
found on both the eastern and western coasts, but the widely dis- 
tributed Sphaeroma walkeri were found on buoys in Hawaii and 
Florida. 
Of the 100 buoys from which isopods and tanaidaceans were taken, 
most (78) contributed only a single species. Two species were taken 
from 16 buoys, three species from five buoys, and four species from 
one (Station 48, Florida Keys region). 
Considering depth occurrence (table 2), we note that 50 percent of 
records of capture of isopods (disregarding number of specimens) 
were within one meter of the waterline on buoys, and that about 
another 25 percent occurred between 1 to 5 meters from the surface. 
In the families Sphaeromatidae and Idoteidae, more than half of the 
records (53 percent and 55 percent, respectively) for each family 
are at 0 to 1 meter depth, and about three-fourths of their occurrences 
are within five meters of the surface. Janirids show the greatest 
range of occurrence, from 0 to 55.4 meters, with Janira alta being 
recorded at the greatest depth for all isopods (on the anchor block 
set at 55.4 meters depth). None of the Jaeropsidae, Cirolanidae, 
Excorallanidae, or Anthuridae was found within a meter of the 
surface, and none of the last three families named was taken at less 
than five meters of the surface. In fact, the single excorallanid and 
