138 



THE MICROSCOPE AND ITS REVELATIONS. 



another, so as to give to the body every variety of motion, but sometimes 

 work altogether. If the sun -light should fall upon them when they are 

 in activity, they display very beautiful iridescent colors. In addition to 

 these ' paddles,' the Cydippe is furnished with a pair of long tendril-like 

 filaments, arising from the bottom of a pair of cavities in the posterior 

 part of the body, and furnished with lateral branches (A); within these 

 cavities they may lie doubled-up, so as not to be visible externally; and 

 when they are ejected, which often happens quite suddenly, the main 

 filaments first come-forth, and the lateral tendrils subsequently uncoil 

 themselves, to be drawn-in again and packed-up within the cavities with 

 almost equal suddenness. The mouth of the animal, situated at one of 

 the poles, leads first to a quadrifid cavity bounded by four folds which 

 seem to represent the oral proboscis of the ordinary Medusae (Fig. 359); 

 and this leads to the true stomach, which passes towards the opposite 

 pole, near to which it bifurcates, its branches passing towards the polar 



FIG. 364. 



FIG. 365. 



Cydippe pileus, with its tentacles 

 extended. 



JBeroe Forskalii, showing the tubular 

 prolongations of the stomach. 



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 seems essentially to consist of sensory ten- 

 tacles. 1 From the cavity of the stomach, tubular prolongations pass-off 

 beneath the ciliated bands, very much as in the true JBeroe (B); these 

 may easily be injected with colored liquids, by the introduction of the 

 extremity of a fine-pointed glass-syringe (Fig. 106) into the mouth. 

 The liveliness of this little creature, which may sometimes be collected 



1 It is commonly stated that the two branches of the alimentary canal open on 

 the surface by two pores situated in the hollow of the fringe, one on either side 

 of the nervous ganglion. The Author, however, has not been able to satisfy him- 

 self of the existence of such excretory pores in the ordinary Cydippe or Beroe, 

 although he has repeatedly injected their whole alimentary canal and its exten- 

 sions, and has attentively watched the currents produced by ciliary action in the 

 interior of the bifurcating prolongations, which currents alwaysappear to him to 

 return as from csecal extremities. He is himself inclined to believe that this ar- 

 rangement has reference solely to the nutrition of the nervous ganglion and ten- 

 tacular apparatus, which lies imbedded (so to speak) in the bifurcation of the 

 alimentary canal, so as to be able to draw its supply of nutriment direct from 

 that cavity. 



