1878.] A New Locality for Cordylophora. 233 
where it empties its cold clear spring waters into the Chesapeake 
bay, for a distance of one hundred and twenty yards up the 
stream, was densely populated with colonies of this beautiful 
organism. Attached to the water-plants (two species of Potamo- 
geton and a Nitella), and to the rocks in the bed, and on the sides 
of the creek, they formed a delicate living fringe to every object 
in the stream. At the mouth of the creek its bed is about forty 
feet wide with a narrow channel on one side, in which the water, 
not over three or four feet in depth, flows very rapidly. In the 
channel where the sunlight is the strongest, owing to the much 
less abundant growth of vegetable life, where the current is most 
rapid, and nearest to the mouth, where the changes in the sur- 
rounding conditions must be greatest, there we found the colonies 
in their greatest luxuriance. The waters of the Chesapeake are 
only brackish in this northern part of the bay, and the tide rises 
and falls but ten or twelve inches; still this is sufficient to make 
quite an appreciable difference in the saltness, density and tem- 
perature of the water for a number of hundred yards up the 
stream. The variations in the conditions then must be consider- 
able and the changes must be quite sudden, as they occur with 
the rise and fall of the tide. The nutritive hydranths too must be 
possessed of great activity and strength to enable them to catch 
and retain their food while the water is dashing by them at such 
a rapid rate. Another visit was made to the same locality in the 
last week in October, when we found the reproductive bodies of 
both sexes in great numbers. In these latter the reddish-brown 
branched spadix showed very distinctly in certain stages of devel- 
opment, ramifying through the opaque-white mass of the gono- 
_ phore, and in later stages becoming resorbed. The specimens 
differ in no important respects from the figures and description of 
Allman. The color is usually a little brighter, being pinkish-red 
instead of reddish-brown; occasionally there are as many as 
eighteen or twenty tentacles, and occasionally the shallow annula- 
tions at the bases of the ultimate ramuli may be absent, but these 
all fall within the range of specific variation. Unlike Prof. Leidy’s 
specimens, those from Curtis’ creek agree in size with -those of 
Prof. Allman. It is interesting to note that in one of the locali- 
ties whére Prof, Allman collected it, he found it associated with 
= — Potamogeton and Lemna, though not attached to them as many 
_ of our specimens were. 
Cordylophora presents three special points of interest: 1. It 
