CLYTIA BICOPIIORA. 79 



glands, extending towards the base of the proboscis. The Hydrarium 

 (see figure of Professor Agassiz in Vol. IV. PI. 29, Fig. 6) grows from 

 three quarters to an inch in height, in small tufts attached to Fucus ; the 

 calycles are strongly compressed (Fig. Ill), and differ as much in their 

 proportions as those of G. cylindrica, when seen from the broad or from 

 the narrow side. This species may yet prove identical with the Clytia 

 Johnstoni of Alder. According to the figure of Wright of the Medusa 

 of Campanularia Johnstoni, it can hardly be distinguished from the 

 Medusa of our Clytia bicophora ; the Medusa of C. vohtbiUs figured by 

 Hincks resembles also closely our Clytia Medusa?. The Medusa figured 

 by Dalyell as the young of M. fimbriata, on PI. 

 52, Fig. 4, Rare and Remarkable Animals of 

 Scotland, is undoubtedly a young Medusa of C. 

 Johnstoni, to judge from its characteristic attitude. 

 If the figure which Gosse has given of the calycle 

 of this same species in his " Devonshire " is correct, 

 there can be but little question as to their specific 

 difference ; the peculiar species figured by Gosse 

 has, however, not been noticed by other English 

 observers. The Medusae of Clytia cylindrica and ' 

 of Clytia bicophora are so alike, immediately after 

 their escape from the reproductive calycles, that 

 when the development of Clytia cylindrica was first discovered, the 

 Medusae which are here figured as Clytia bicophora (Fig. 41, Agassiz's 

 Cont. Nat. Hist,, p. 307) were mistaken for the adult of the Medusae of 

 Clytia cylindrica. As the Clytia bicophora is very common at Nahant, 

 the complete development of the Medusa has been traced, and the 

 error is here corrected. 



Eastport, Maine (W. Stimpson) Massachusetts Bay (Agassiz) ; Vine- 

 yard Sound and Naushon (L. and A. Agassiz). 



Cat. No. 133, Eastport, Maine, July, 1852, W. Stimpson. Hydrome- 

 dusarium. 



Cat. No. 134, Beverly, Mass., July, 1861, A. Agassiz. Hydrarium. 



Cat, No. 135, Vineyard Sound, July, 1849, L. Agassiz. Hydromedu- 

 sarium. 



Cat, No. 136, Grand Manan, August, 1857, J. E. Mills. Hydromedu- 

 sarium. 



Cat, No. 137, Nahant, Dec, 1855, H. J. Clark. Hydromedusarium. 



Cat, No. 154, Eastport, Maine, July, 1852, W. Stimpson. 



Cat, No. 401, Nahant, June, 1862, A. Agassiz. Hydromedusarium. 



Cat. No. 443, Nahant, June, 1864, A. Agassiz. Medusa. 



Museum diagram No. 17, after L. and A. Agassiz. 



Fig. 111. Sterile Hydra and reproductive calycle, seen from the broad side. 



