THE HYDROIDS OF BERMUDA.i 

 Edgar Davidson Congdon. 



Presented by E. L. Mark, November 14, 1906. Received November 2, 1906. 



This paper has for its purpose the description of certain hydroids 

 which I collected in the summer of 1903, while an attendant at the 

 Bermuda Biological Station. They were investigated under the guid- 

 ance of Dr. C. W. Hargitt in the Zoological Laboratory of Syracuse 

 University. I wish to express my great indebtedness to Dr. Hargitt 

 for his suggestions and criticisms, and to thank the Bermuda Biological 

 Station for courtesies extended to me during the season. 



Verrill ('99, p. 571) has stated in the Proceedings of the Connecticut 

 Academy of Science that eleven hydroids occur at Bermuda, but he 

 does not name or describe them. I know of no other zoologist who 

 has occupied himself with the subject. 



Of the eighteen species that were found, eight were previously un- 

 described. Each species which had been previously described varied 

 in some small degree from the type individuals. The various common 

 hydroid families are quite equally represented. Eudendrlum hargitti, a 

 new species, is especially interesting because of phenomena of oogenesis 

 which have been elsewhere described (Congdon, : 06). Two new species 

 of Halecium present female gonophores whose structures are significant 

 when compared with the gonophores of other species of the genus. 



Few hydroids are found on the exposed southern shore of the Ber- 

 mudas. The coves, inlets, and reefs of the opposite shore are well 

 supplied with individuals and species. The Sargassum, which floats in 

 after a prolonged south wind, often is the home of an abundance of 

 Aglaophenia minuta, Halecium, and Clytia simphx. 



Pennarla tiarella, Eudendrlum ramomm, Sertularia humilis, and 

 Sertularella hrevicyatkus are the most common species. E. hargitti^ 

 Sertularella speciosa, and TJip-oscyphus intermedius are each confined 

 to some single very restricted locality. In the few places especially 

 favorable to hydroid life the strife for foothold is so marked that seven 

 of the small species may be found growing on the larger ones. 



^ Contributions from The Zoological Laboratory, Syracuse University ; also 

 Contributions from the Bermuda Biological Station for Research, No. 9. 



