MEDUSIDM. 157 



to the phenomena of their development. 3. That many otner so-called 

 Medusidce. may from analogy be regarded, as in like manner, medusi- 

 form gonophores. 4. But that there may exist, nevertheless, a group 

 of medusid forms, which may give rise, by true reproduction, to 

 organisms directly resembling their parents, and therefore worthy of 

 being placed in a separate order, under the name of Medusidce. 

 According to Gegenbaur, the following families would belong to this 



Fig. 52. yEquorea violacea, natural s-ze (Milne-Edwards). 



order: OceanidcR, Thaumantidce, ^Eguoridece (Fig. 52), Eucopidce, 

 Trachynemidce, Geryonidce, /Eginidce. 



In the second division, these included under the family Lucer- 

 nariadcz, the body is more or less cup-shaped, and frequently 

 about an inch in height, terminating proximally in a stalk of variable 

 length, and furnished with a free umbrella, which differs from a necto- 

 calyx, with which it is often confounded, by the absence of a veil, in 

 its mode of development, and in the nature of its canal system, having 

 never less than eight radiating canals, and in the nature of its marginal 

 bodies. If we regard this second division as an order, we may 

 arrange it under two principal sections. In the first, including the 

 genera Pelagia and Lucernaria^ the primary result of the generative 



