THE HYDROIDS OF THE WOODS HOLE REGION. 



By C. C. NUTTING, 

 L _ Professor of '/.oology. University of l&uta. 



INTRODUCTORY NOTE. 



The limits of the "Woods Hole region," in the sense hero, used, may be roughly 

 defined as follows: Starting with the point of Cape Cod as the northern and eastern 

 limits, following the New England coast to New London, Conn. ; thence southward to 

 the end of Long Island; thence southeast to the edge of the Gulf Stream, which is 

 followed until off Cape Cod. These limits embrace, roughly, the area that can be 

 covered by one-day excursions by steamer from the U. S. Fish Commission station 

 at Woods Hole, Massachusetts. 



It is the purpose of this pamphlet to furnish collectors and workers in this 

 region with a practical and concise means of identifying the species of hydroids known 

 to occur within the area above described. There are a number of other species that 

 almost certainly occur within the Woods Hole region, but with one or two exceptions, 

 involving species of unusual interest, these will be omitted. 



Most of the material studied in connection with this work was secured by the 

 author during three summers spent at the U. S. Fish Commission laboratory at 

 Woods Hole and a month at the laboratory of Dr. Alexander Agassiz, at Newport. 



The number of species listed indicates a fairly rich hydroid fauna in the region, 

 the general relation being with the Arctic or rather Ilolarctic fauna, which explains 

 the large percentage of British forms represented on our Atlantic coasts. 



The illustrations are from sketches originally made by the author to illustrate a 

 monograph of the North American hydroids, in course of publication by the United 

 States National Museum. Permission was given by the authorities of that institution 

 to have ink tracings made from these sketches, which have been reduced in size and 

 used in the present work. 



In order to secure the brevity necessary for the treatment of the subject in the 

 form of a practical guide to identification, it has been necessary to omit all discussion 

 regarding synonomy. In naming genera and species a conservative course has been 

 followed, although the names in some cases have been changed in what will doubtless 

 appear to be an arbitrary manner. The reasons for these changes are in -all cases 

 briefly indicated, but the explanations are not so full as would be deemed requisite in 

 a Work of more strictly technical nature. 



Much remains to be done before we can discuss with profit the economic bearings 

 of the subject of this work. It is well known, however, that many fishes feed more 



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