THE AXIAL GRADIENTS IN HYDROZOA. VIII. 



RESPIRATORY DIFFERENCES ALONG THE 



AXIS IN TUBULARIA WITH SOME 



REMARKS ON REGENERATION 



RATE. 



L. H. HYMAN, 

 HULL ZOOLOGICAL LABORATORY, UNIVERSITY OF CHICAGO. 



AXIAL DIFFERENCES IN OXYGEN CONSUMPTION. 



The experiments recorded in this section were performed at 

 Swan's Island, Maine, in August, 1924. This island is one of a 

 group off the coast of Maine, opposite Rockford, and is directly 

 south of Mt. Desert Island. My visit to Swan's Island was 

 occasioned through information received from the Anglers Com- 

 pany (now the Denoyer-Geppert Company) that Tubularia 

 flourishes in that locality during the summer months, at which 

 season, as is well known, it is in poor condition at Woods Hole. 

 The company further kindly invited me to make use of their 

 collecting station and equipment located on Swan's Island. I 

 am greatly indebted to the company in all of these matters and 

 particularly to Mr. Philip Turner, a member of the firm, for 

 assistance in collecting Tubularia. 



The collecting station at which these experiments were per- 

 formed is situated in the town of Swan's Island, which town is 

 located at the head of a large harbor and is provided with the 

 usual wharves, pilings, etc. Tubularia was found in large quan- 

 tities on the pilings of the steamer wharf and is apparently re- 

 stricted to this one habitat. Members of the Anglers Company 

 informed me that they had never seen it in any other situation 

 nor on any other of the wharves or pilings. Large quantities of 

 the hydroid were readily obtained at low tide from the piles 

 supporting the wharf. 



The Tubularia occurring at Swan's Island does not seem to be 

 identical with the T. crocea of Woods Hole. The stems are much 

 more elongated and branching less frequent. These character- 



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