1892] MARYLAND ACADEMY OF SCIENCES. 223 



depth of twelve feet, and while dredging in the adjacent 

 channel, thirty yards northeast of the pier, at a depth of 

 twenty feet, a few steins of Cordylophora (bearing 

 hydranths) attached to oyster shells were bronght up. 



I visited the Fort several" times later in the summer, 

 and again late in September, and on every occasion found 

 the colonies in good condition, and bearing gonophores.* 



I have made no observations farther down the Patapsco 

 than Fair Yiew, but we shall later see that there is good 

 reason for believing that the colonies exist not only at the 

 mouth of this estuary, but in the upper portion of the 

 Chesapeake Bay proper, at least as far southward as 

 Annapolis. 



Only one estuary north of the Patapsco has been visited, 

 viz.. Back Kiver. In the spring of 1891, Mr. Price and 

 myself examined the supports of the Philadelphia and 

 Wilmington railroad bridge, also those of the Eastern 

 Avenue bridge, with a negative result. At that date the 

 waters were, and had been for a considerable period, much 

 clouded by washings from the railroad cuts and embank- 

 ments near the head of tide-water. This circumstance, 

 together with the fact that comparatively few large vessels 

 (which, as already suggested, are probably an imj)ortant 

 dispersing agent for the species), enter this estuary, dis- 

 couraged further search in its upper waters. 



I am informed by Professor Basil Sellers tliat in 1889 he 

 found Cordylophora in the Magothy, attached to the 

 wooden supports of the so-called New Bridge, which spans 

 the estuary of this river about one mile below the head of 

 tide. He also found colonies attached to the submerged 

 stems and leaves of certain aquatic plants growing near 

 the bridge. Early in August last, while members of my 

 classes were studying the development of the oyster at the 



* On Nov. 12, however, it was found that the hydranths and stems of the colonies 

 had mostly disappeared. 



