340 
BULLETIN OP THE BUREAU OF FISHERIES 
tion was limited as just described. It occurred in water of a salinity ranging from 
about 13.00 to 26.00, or more. 
Two species, Bowerbankia gracilis var. caudata and fVictorella pavida, have a 
greater range from north to south, according to the data at hand, than any other species 
collected. The former was found at areas B, I, L, P, and S' in water of salinities 
ranging from 23.87 to 15.71 per mille, while the latter, which, as Osburn has pointed 
out, is supposed to frequent waters of only slight salinity, was dredged at areas A, C, 
K, and S, which range from Cape Charles City to the region of James Island. The 
salinities ran from 27.06 to 17.44 per mille. 
The distribution of Anguinella palmata is of interest since it was found only well 
within the bay— a distribution which appears to be characteristic of the species, 
according to Osburn. It was collected almost exclusively from the region close to 
the mouth of the Potomac River. During the cruises of July, August, and December, 
1920, and January and March, 1921, it was dredged at area /; in December at areas 
J and L; in January at area N, and in December at area H. Areas I, J, and L lie 
close to the mouth of the Potomac, N just inside the mouth, and H a little farther 
south at the entrance of the Rappahannock River. The salinities of the water 
ranged from 13.19 per mille at area N to 21.10 per mille at area J. 
Hemiseptella denticulata was found at many areas in the lower half of the bay 
but not north of area L. It was collected from water ranging in salinity from 14.72 
to 26.44 per mille. 
Undoubtedly the presence of solid objects upon which the Bryozoa may attach 
themselves constitutes an important factor affecting the distribution; but the apparent 
confinement of one species, at least, to the region of the mouth of the bay, the taking 
of one only from the waters around the mouth of the Potomac River with the reports 
of a slightly brackish habitat for this species in other regions of the Atlantic coast, 
and the total lack of specimens in our collection of over 70 colonies from above area 
S indicate that the degree of salinity is a factor in determining the distribution. At 
least, as Osburn has stated, no specimens were taken in waters of a salinity lower 
than one-third of the salinity of pure sea water. Not much can be said concerning 
the influence of temperature, but several of the species seem to be able to withstand 
the winter and summer extremes of temperature found in the offshore waters at the 
bottom (about 2° to 25° C.). 
The salinities given in this section on the Bryozoa are those determined from bottom 
samples; and they are probably the ones in which the various specimens were grow- 
ing; but in some cases the specimens were taken on old hy droid stems which may 
have been unattached to the bottom but probably drifting about very close to it. 
ANNELIDA 
. 
The collection of polychaetous annelids is rather small, but this is largely due to 
the fact that all of the material was dredged and to the fact that only the offshore 
waters of the bay were studied. 
The species listed below were collected during the August, October, December 
(1920), and January, March-April (1921) cruises. All of the identifications were 
made by Dr. A. L. Treadwell. The following species have been identified by him 
(three of the species are new) : Lepidonotus squamatus Linnaeus, L. variabilis Web- 
ster, Harmothoe aculeata Andrews, Paranaitis speciosa Webster, Nephthys ingens 
Stimpson, N. phyllocirra Ehlers, N. verrilli McIntosh, Sphaerosyllis jortuita Webster, 
