BIOLOGICAL STUDY OF CHESAPEAKE BAY WATERS 
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bay. It was found at a depth of 23 meters in a region of black mud and sand during 
the December, 1920, cruise. (Salinity 30.96 per mille, water temperature 11.6° C.). 
The large tube-inhabiting annelid Diopatra cuprea is undoubtedly a common 
form on muddy sand flats in Chesapeake Bay, since it is known to be common in 
shallow waters along the coast from South Carolina to Cape Cod (Pratt, 1916, p. 
290). Our collections were made by dredging in the comparatively deep parts of the 
bay; and since it is seldom possible to catch this worm except by careful digging, 
it is not surprising that only one specimen was obtained. This one, strange to say, 
was collected in the beam trawl which contained in addition a large quantity of speci- 
mens of various sorts. It was taken during the March-April cruise, 1921, at area A 
off Cape Charles City where there was considerable black mud — in other words, in 
one of the “deep holes” of the bay (43 meters). The salinity and temperature of 
the water were 28.27 per mille and 11.5° C. 
Another tube-dwelling annelid that has been found along our Atlantic coast 
from North Carolina to Cape Cod and which, as Treadwell has pointed out, is difficult 
to capture, is Chaetopterus. It undoubtedly is fairly abundant in Chesapeake 
Bay, for many fragments of tubes (one with a piece of the worm inside) were col- 
lected. These were all taken in the lower half of the bay from the mouth of the 
Potomac River to the region of Cape Charles (areas Q, 0, C, B, A, E, F, and G). The 
salinities and temperatures of the water in which the tubes were found ranged from 
17.70 to 28.08 per mille and 10.1° C. to 24.8° C. 
Streblospio benedidi has been reported by Webster (1886, p. 150) and by Webster 
and Benedict (1884, p. 728) from the shores of New Jersey and Maine. Our survey 
has dredged it from the upper part of Chesapeake Bay, in shallow water only (10 to 
22 meters). Webster has spoken of it as being abundant on Mytilus beds and in 
ditches to which the tide has access. The indications are, judging from these obser- 
vations and from the fact that this species was found as far north as Bloody Point 
(areas V and W) in Chesapeake Bay, that it is at home in brackish water. The 
salinities of the water in which the six specimens in our collection were found ranged 
from 10.08 to 17.27 per mille. They were dredged during the July and October 
cruises in water whose temperature was 20° C. to 23° C. 
Two species of Scolecolepis ( Scolecolepis viridis and S. tenuis) are known from 
the Chesapeake. The former occurs in large numbers within a small area in certain 
places (for example, area V, which is close to the mouth of the Severn River). This 
species is known from Cape Cod to New Jersey. Evidently it can live in water of 
low salinity, for all of the specimens collected by our survey came from water the 
salinity of which was not more than 16.60 per mille. Specimens were especially 
abundant at an area where the salinity was as low as 9.16 per mille. Specimens were 
collected on the January and March-April, 1921, cruises when the water temperature 
was as low as 1.3° C. Only a few small specimens of S. tenuis were collected, and 
these came from area B not very far from the mouth of the bay (salinity 23.87 per 
mille, temperature 20.0° C., October, 1920). 
Large numbers of specimens of Polydora ligni were collected. Treadwell speaks 
of this species as being “the species represented by the largest number of individuals 
in the collection.” Many of the specimens were larval forms, however, and even the 
adults did not seem to be sexually mature. The larval forms were found distributed 
all over the bay, but those which had reached the adult form seemed to be restricted 
to the lower half. 
