EUCOPE PARASITICA. 



87 



Fig. 126. 



from actual observations, in what manner these differences of the 

 young Medusas are carried out in the adult. The Hydrarium and the 

 Medusa of several species are described here under the generic name 

 of Eucope, simply to call attention to the great structural differences 

 found among Campanularians apparently so closely related. 



Eucope polygena is remarkable for the short stems of the sterile 



Hydra, the stoutness of the main 



/ 



stem, and the great number of Me- 

 dusae developed in a single reproduc- 

 tive calycle ; the bell is flaring, with a 

 smooth edge, and rather shallow ; the 

 reproductive calycles are elliptical, 

 slightly wavy (Fig. 126), and some- 

 what bottle-shaped at the extremity. 

 The Medusa resembles closely that 

 figured by Professor Agassiz as Eu- 

 cope diaphana, in Vol. IV. PI. 34, Fig. 

 9, Contributions to the Natural His- 

 tory of the United States ; the tenta- 

 cles are larger in proportion to the 

 size of the disk. This species is found 



growing on stems of Laminaria, in small branching tufts, of one to two 

 inches in height. 



Cat. No. 393, Nahant, June, 1862, A. Agassiz. Hydromedusarium. 



Cat. No. 399, Nahant, June, 1862, A. Agassiz. Hydromedusarium. 



Eucope parasitica A. AGASS. 



This species is closely allied to the E. polygena ; it has, like it, short 

 branches, composed of not more than three or four rings, supporting 

 the sterile Hydras ; the inner walls of the stems are parallel to the 

 outer wall ; the sterile Hydras go off nearly at right angles to the 

 stem ; the reproductive calycles are very graceful, terminating with a 

 peculiar mitre-shaped top. The Medusa has twenty-four tentacles ; it 

 has thus far only been found growing on a species of Penella, parasitic 

 on Orthagoriscus mola. 



Massachusetts Bay, Nahant (A. Agassiz). 



Cat. No. 80, Nahant, August, 1861, A. Agassiz. Hydromedusarium. 



Cat. No. 81, Nahant, August, 1856, L. Agassiz. Hydromedusarium. 



Fig. 126. Magnified view of part of main stem of E. polygena. 



