CONTRIBUTIONS FROM THE BERMUDA BIOLOGICAL STATION 



FOR RESEARCH. No. 136. 



ADDITIONS TO THE HYDROID FAUNA OF THE 

 » BERMUDAS. 



By Rudolf Bennitt. 



Received February 15, 1922. Presented by E. L. Mark. 



The hydroids which have been studied in the preparation of this 

 paper are from two sources, namely, the collection made by the writer 

 during the summer of 1921, and those made at various times since 1903 

 by Dr. E. L. Mark and others in attendance at the Bermuda Biological 

 Station. I am greatly indebted to Dr. Mark, both for having made 

 my stay at Bermuda possible and for having given me the opportunity 

 of examining for hydroid material his miscellaneous collections. 



The only papers hitherto written on the Bermuda hydroids are by 

 Congdon (1907) and Ritchie (1909). Congdon described 19 species, 

 of which five (Eudendrimn hargitti, Clytiafragilis, Sertularella speciosa, 

 Scrhdaria humilis, and Thyroscyphus intcrmcdius) are new. Several 

 others, described by him as new, have been shown by later writers, 

 notably Nutting and Fraser, to belong to already established species, 

 Ritchie discusses the synonymy of one of the Bermuda campanula- 

 rians, and extends the range of two "Challenger" hydroids from the 

 West Indies to the Bermudas. 



Fraser's paper (1912) on the hydroids of Beaufort, N. C, is also a 

 valuable aid in the study of the Bermuda hydroids, since 21 species of 

 the latter, or over half of the Bermuda forms, occur also in the Beau- 

 fort region. The strong affiliation of the hydroid fauna of the Ber- 

 mudas with that of the West Indian region, already suggested by 

 Congdon, is still more strikingly demonstrated by the species now 

 reported from Bermuda; in all, 29 species are common to the two 

 regions. 



The distribution of the individual species found in Bermuda is 

 shown in the following table: — 



