214 TKANSACTIONS OF THE [1892 



pied with these experiments, I became so much interested 

 in this curious and beautiful animal that I have been drawn 

 somewhat beyond the point to which I first intended car- 

 rj'ing my investigation. 



It seems to me that there are a number of good reasons 

 why a thorough knowledge of the structure and habits of 

 Cordj^lophora is desirable. Among these should be men- 

 tioned the fact that this form constitutes an admirable type 

 with which to introduce the young zoologist to the study 

 of hydroid morphology and physiology (cf. 1. p. 181), 

 especially at points like Baltimore, Philadephia, or Wash- 

 ington, where the living oceanic hydrozoa are less easily 

 accessible. 



Certain of my experiments lead me to believe that Cor- 

 dylophora may easily be transferred from our estuaries far 

 into the interior (cf. 4- p. 709), and kept alive for several 

 weeks, at least, in aquaria of brackish water artificially 

 made. This would render it possible for inland students 

 to study this interesting form alive, which would greatly 

 stimulate their interest in, and serve to clear up their 

 knowledge of, a group, which, in the interior, has its only 

 representative in the fresh-water hydra. 



Though I have given considerable time and attention 

 to the collection of the data contained in the following 

 pages, the study has been of the nature of a recreation. I 

 trust, however, that the facts presented may not be less 

 useful for having been acquired chiefly during a series of 

 pleasant outings. 



The first locality in the Chesapeake basin of which I 

 have seen printed notice, was observed in 1877 by Profes- 

 sors Uhler, Brooks, and S. F. Clark (9, p. 32), near the 

 mouth of Curtis Creek. This, however, was not the first 

 observation of the hvdroid in these waters, since Professor 

 Uhler informs me that when a bov he used to fish 



