330 
BULLETIN OF THE BUREAU OF FISHERIES 
CNIDARIA 
HYDROZOA 
The hydroids collected in the deep waters of Chesapeake Bay have been studied 
by Charles W. Hargitt. He has identified 14 species and listed those identified and 
described for Chesapeake Bay by C. C. Nutting (1901) and S. F. Clarke (1882). By 
far the most abundant hydroids collected by our survey belong to the genus Thuiaria. 
Three species, one of which at least is of commercial importance, have been reported 
from the bay and its tributaries by Nutting. They are Thuiaria argentea Linn., T. 
cupressina Linn., and T. plumulijera Allman. Hargitt in working over the collec- 
tions of the year 1920 found T. argentea at many stations and speaks of it as “by 
all odds the most common species taken.” The beam trawl hauls show that 
Thuiaria was found widely distributed over the deeper parts of the bay; but the 
indications are, as has been pointed out by Radcliffe in the log for the 1916 cruises 
and by Hargitt, that some of the material taken was unattached to the substratum, 
although not floating at the surface. Ordinarily roots were not found on the speci- 
mens. Floating hydroids have been observed by Bigelow (1915) on Georges Bank 
off Cape Cod and their occurrence is discussed by C. McLean Fraser in Bigelow’s 
paper (1915). R. C. Osburn, who has studied the Bryozoa collected in the Chesa- 
peake by this survey, has commented on the large amount of dead hydroid material 
received by him with Bryozoa attached, and suggests that they were brought into the 
bay by tides and currents from near the mouth, where they grow. The observations 
of Radcliffe (1916) showed that Thuiaria had increased in abundance during the 
March and April cruises as compared with the supply during the previous winter. 
The indications are that the Thuiaria species can withstand a large range of salinities 
and of temperatures. 
The following hydroids are known to occur in the region of Fort Wool, Va. : 
Calyptospadix cerulea Clarke, Eudendrium carneum Clarke, Styladis arge Clarke, 
Lovenella gracilis Clarke, Bougainvillia rugosa Clarke, and Hydradinia echinata Flem- 
ing. Several other Iwdroids have been collected from Chesapeake Bay, and they are 
now in the United States National Museum. The following list is available owing 
to the courtesy of Waldo S. Schmitt, curator of invertebrates: Campanularia sp., 
Thuiaria argentea (L) from Jerome Creek, Md., T. cupressina (L) off Virginia, T. 
plumulijera Allman, Aglaophenia rigida Allman, Clado carpus jlexilis Verrill off Virginia, 
Antennularia americana Nutting, A. antennena (L), A. simplex Allman, Plumularia 
jloridana Nutting, and Plumularia, near alternata. Two of these species, A. anten- 
nena and P. “near alternata,'” were determined by Verrill and the rest 'by Nutting. 
HYDROMEDUSAS 
The hydromedusse collected during the July, August, October, and December 
cruises of 1920 and the January and March cruises of 1921 have been examined and 
identified by H. B. Bigelow. I am indebted to him for the information that the 
collection contains no new species and that no extensions of any importance to the 
geographic ranges were found. He points out that there are very few species, and 
that the well-known form Nemopsis bachei greatly predominates in the collection. 
This form, which occurs very abundantly along the Atlantic coast near the mouths 
of large bays into which pure ocean water has free access (Mayer, 1910), was found 
widely|distributed in Chesapeake Bay during the cruise of December, 1920. It was 
