NOTES ON THE VARIATIONS OF RHEGMATODES. 



CHAS. W. HARGITT.! 



During the summer of 1900 I collected about two hundred 

 specimens of RJicginatodes temiis for the purpose of studying its 

 development. But this I was unable to carry out, owing to the 

 inability of keeping the medusae long enough in the aquarium to 

 secure the eggs, few seeming to bear ripe gonads at the time of 

 capture. 



It was observed that many specimens showed more or less 

 variability, and attention was then directed toward a study of the 

 variations exhibited among the various organs. The compara- 

 tively few specimens obtained led to the postponement of a final 



study of the problem, hoping to 

 secure additional material. This 

 has been carefully sought during 

 three subsequent summers, but 

 in vain; only during 1902 have 

 any specimens at all been found, 

 and these very few and imma- 

 ture. The following "Notes" 

 are therefore submitted as a slight 

 contribution to the general prob- 

 FIG. i. Rhegmatodes temds. Semi- i em o f variation among Hydro- 



diagrammatic. , , 



medusae, a more extended ac- 

 count of which was made by the writer in I9OI. 2 



The general features of Rhegmatodes are shown in Fig. I. The 

 medusa varies in size at maturity from about 50 to 95 mm. in 

 diameter. In younger stages the shape is more or less hemi- 

 spherical, the tentacles and radial canals very much fewer in 

 number, the earliest stage which I have found having but four 

 canals and four tentacles. With growth the number increases 

 very largely, but they are not correlated as at first, the latter be- 

 coming more numerous, besides also varying numbers of ten- 



1 Contributions from the Zoological Laboratory, Syracuse University. 

 2 BioL. BULL., Vol. II. 



368 



