ALTERNATE AND EQUIVOCAL REPRODUCTION. 



133 



ally formed, the four corners (&, f) become elongated, 

 and by degrees are transformed into tentacles (c). These 



b chid 



a 







e f g Fig. 142. k 



tentacles rapidly multiply, until the whole of the upper 

 margin is covered with them (g). Then transverse 

 wrinkles are seen on the body at regular distances, ap- 

 pearing first above and extending downwards. These 

 wrinkles, which are at first very slight, grow deeper and 

 deeper, and at the same time, the edge of each segment 

 begins to be serrated, so that the animal presents the ap- 

 pearance of a pine cone, surmounted by a tuft of tentacles 

 (h) ; whence the name of Strobila, which was originally given 

 to it, before it was known to be only a transient state of the 

 jelly-fish. The separation constantly goes on, until at last 

 the divisions are united by only a very slender axis, and 

 resemble a pile of cups placed within each other (i). 

 The divisions are now ready for separation ; the upper 

 ring first disengages itself, and then the others in succes- 

 sion.* Each segment (d) then continues its development by 

 itself, until it becomes a complete Medusa (k] ; while, 

 according to recent researches, the basis or stalk remains 

 and produces a new colony. 



347. It is thus, by a series of metamorphoses, that the 

 little animal which, on leaving the egg, has the form of the 



; These free segments have been described as peculiar animals, under 

 the name of Ephyra. 



12 



