

CYDIPPE I BEROE. 547 



divisions are obliterated ; tubular prolongations of the Stomach 

 extend themselves over the disk ; and from its borders there sprout 

 forth tendril-like filaments, which hang down like a fringe around 

 its margin. From the four angles of the Mouth, which, even in 

 the youngest detached animal, admits of being greatly extended 

 and protruded, prolongations are put forth, which form the four 

 large Tentacles of the adult. And finally the Generative organs 

 make their appearance in four chambers disposed around the 

 stomach, which are occupied by plaited membranous ribands con- 

 taining Sperm-cells in the male and Ova in the female; and the 

 Embryoes evolved from the latter, when they have been fertilized 

 by the agency of the former, repeat the extraordinary cycle of 

 phenomena which has been now described, developing themselves 

 in the first instance into Hydraform Polypes, from which Medusoids 

 are subsequently budded-off.* 



424. In connection with the preceding, it will be convenient to 

 mention two curious little Marine animals of frequent occurrence, 

 upon the true place of which in the scale Zoologists are not alto- 

 gether agreed, but which, having the free-swimming habits, the 

 soft texture, and the luminosity of the Medusa?, have been very 

 commonly ranked as members of the same group. One of these is 

 the Cydipjie jtileus (Fig. 281, a), very commonly known as the 

 Beroe, which designation, however, properly appertains to another 

 animal (b) of the same grade of organization. The body of 

 Cydip2)e is a nearly-globular mass of soft jelly, usually about 

 3-8ths of an inch in diameter ; and it may be observed, even with 

 the naked eye, to be marked by eight bright bands, which proceed 

 from pole to pole like meridian (lines. These bands are seen with 

 the Microscope to be formed of rows of large flattened Cilia, which 

 are in a state of pretty-constant vibration, though sometimes they 

 are at rest; and if the sun-light should fall upon them when they 

 are in activity, they display very beautiful iridescent colours. 

 The Mouth of the animal, situated at one of the poles, leads first 

 to a quadrifid cavity bounded by four folds, which seem to the 

 Author to represent the oral proboscis of the ordinary Medusae 

 (Fig. 278); and this leads to the true Stomach, which passes 

 towards the opposite pole, near to which it bifurcates, its branches 

 passing towards the polar surface on either side of a little body 

 which has every appearance of being a Nervous ganglion, and 

 which is surmounted externally by a fringe-like apparatus that 



* Hence there is not a true ' Alternation of Generations ' in this case, 

 any more than in the preceding (§ 414), the only difference between the 

 two consisting in this, — that the Zoophytic phase of life is that which is 

 most conspicuous in the Campanularidce and Tubularidce ; their Medu- 

 soids being small and rudimentary, and sometimes not being detached 

 at all ; whilst in the Lif e-history of the ordinary Jelly-fish, the Zoophytic 

 stage is passed in such obscurity as only to be detected by careful research, 

 its Medusan product being that which becomes conspicuous. 



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