50 



MAKINE ANIMALS OF MASSACHUSETTS BAY. 



from which most of our Jelly-fishes are developed. They differ 

 in one "essential feature from the Tubularians. (Fig. 93.) The 

 whole stem, from summit to base, is enveloped in a horny sheath, 

 extending around both the fertile and sterile individuals of the 

 community, and forming a network at the base of the stem, 

 which serves as a kind of foundation for the whole stock. To 

 the naked eye such a community looks like a tiny shrub (see 

 Fig. 57), with the branches growing in regular alternation on 

 either side of the stems. The reproductive calycles, i. e. the pro- 

 tecting envelopes covering the young Medusae, usually arise in 

 the angles of the branches formed by a prolongation of the 

 sheath. These calycles or bells, as they are called, assume a 

 gi'eat variety of shapes, — elliptical, round, pear-shaped, or ringed 

 like the Clytia. (Fig. 72.) In one such bell there may be no 

 less than twenty or thirty Medusas developed one below the 

 other ; when ready to hatch, thp calycle bursts and allows them 

 to escape. 



Eucope. (Eucope diaphana Ag.) 



In Figs. 60 and 61 we have a representation of our little 

 Eucope, one of the prettiest of the Jelly-fishes belonging to this 



Fig 57. 



Fig. 58. 



group ; Fig. 57 represents the Hydroid from which it arises ; a 

 single branch with the reproductive bell being magnified in Fig. 



rig. 57. Hydraxium of Encope ; natural size 

 Fig. 53. Portion of Fig. 67 ; magnified. 



