BIOLOGICAL STUDY OF CHESAPEAKE BAY WATERS 
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ature of water 23.2° C., July, 1920, cruise.) The second, which is known from Cape 
Cod to North Carolina, was represented only by immature forms. The third, which 
was described by Andrews from Beaufort, N. C., came from a depth of 28 meters 
where the bottom was a mixture of clay, shells, sand, and mud. (Salinity (?) and 
temperature of the water 10.1° C., December, 1920, cruise.) 
The annelid collection as well as the data on salinity, temperature, depth, char- 
acter of the bottom, seasonal distribution, and distribution from the head of Chesa- 
peake Bay to its mouth, deal with the deeper portions of that body of water, which 
naturally were the only regions that could be visited by the U. S. S. Fishhawk and the 
U. S. S. Albatross. The shore which includes the more or less steep strip between 
high and low tide, the sand flats, the mud flats, the quiet bays, etc., remain to be 
investigated. 
It seems probable that the character of the bottom for some burrowing and tube- 
forming annelids is important — at least regions where there is deep, soft, foul mud are 
unfavorable habitats for nearly all of the polychaetous annelids. Some places on 
the bottom of the bay are covered with such deposits; and, in general, the deeper 
parts of the bay show a layer of firm mud of varying thickness. It is of interest to 
note that the only two really common annelids taken in the bay, Nereis limbata and 
Polydora ligni, are known to live in muddy regions, the former frequenting foul and 
brackish waters and the latter making use of mud in constructing its fragile tubes. 
Both of these species showed a wide distribution over the areas visited on our cruises. 
On the other hand, there are regions of sand here and there all over the bay, so that 
if the presence of these sandy places is all that is necessary for the life of worms that 
make tubes of grains of sand, such annelids might be found widely distributed over 
the bay. 
It is known that many annelids live on the organic matter which is found in the 
sand or mud in which they burrow (M’lntosh, 1885, p. ix), as in the case of Arenicola 
marina (Flattely and Walton, 1922, p. 192, from Davison, 1891), that others such as 
Cirratulus tentaculatus (Flattely, 1916) while living buried in sandy mud do not pass 
it through the alimentary canal but select nutritive food particles — for example, algal 
spores, diatoms, and general organic debris outside of the body. Also it is known, 
according to Flattely (1922, p. 192), that tube worms such as Sabella, Pectinaria, 
Sabellaria, Serpula, etc., depend for their food on currents set up by the cilia on the 
gill filaments. Still others devour small crustaceans, zoophytes, and sponges; and a 
few, according to M’lntosh (1885, p. ix), feed on Fuci and other algae. Such a variety 
of feeding habits must be a factor in the distribution of the polychaetous annelids in 
Chesapeake Bay, although our data are not of a character to throw much light on such 
a relation. Shore, sand-flat, and mud-flat observations should be ideal for studying 
a problem of that sort. 
There are forms which stick to the underside of rocks and inside of shells, or hide 
in rocks and crevices, or conceal themselves between ascidians, barnacles, roots, 
cavities of sponges, etc., such as species of Lepidonotus, Harmothoe, and others 
(Verrill and Smith, 1873, p. 397). 
Also some annelids, such as species of Sabellaria, Serpula, Sabella and Spirorbis, 
form tubes which are attached ordinarily to rocks, stones, shells, etc. (Verrill and 
Smith, 1873, pp. 321-323). Habits of this sort which depend on the presence of large 
more or less stationary bottom materials must also have an effect on distribution. 
No close relationship of distribution to temperature can be made out, although 
the data show that many of the species are able to live in water of a wide range of 
