882 SPONGES AND ZOOPHYTES 



this order is furnished by the Cydippe^ j) ileus (compare fig. 669), very 

 commonlv known as the Seroe, which designation, however, properly 

 appertains to another animal (fig. 670) of the same grade of organisa- 

 tion. The body of Cydippe is a nearly globular mass of soft jelly, 

 usually about |ths 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 row T s of flattened 

 filaments, far larger than ordinary cilia, but lashing the water in 

 the same manner ; they sometimes act quite independently of one 

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

 sometimes work all together. If the sunlight should fall upon them 

 when they are in activity, they display very beautiful iridescent 

 colours. In addition to these ' paddles ' the Cydippe is furnished 

 with a pair of long tendril-like filaments, rising from the bottom of 

 a pair of cavities in the posterior part of the body, and furnished 

 withlateral branches ; 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 sudden- 

 ness. The mouth of the animal situated at one of the poles leads- 

 first to a quadrifid cavity bounded by four folds which seem to repre- 

 sent the oral proboscis of the ordinary Medusa; (fig. 664) ; 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 seems essentially to consist of sensory 

 tentacles. 2 From the cavity of the stomach tubular prolongations 

 pass off beneath the ciliated bands, very much as in the true Beroe. 

 These may easily be injected with coloured liquids by the intro- 

 duction of the extremity of a fine-pointed glass syringe into the 

 mouth. The liveliness of this little creature, which may sometimes 

 be collected in large quantities at once by the stick-net, renders it a 

 most beautiful subject for observation when due scope is given to its 

 movements; but for the sake of microscopic examination, it is of 

 course necessary to confine these. Various species of true Beroe, 3 

 some of them even attaining the size of a small lemon, are occasionally 

 to be met with on our coasts, in all of which the movements of the 



1 More correctly Hormiphora 



- 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 

 inT\ons ganglion. The Author, however, has not been able to satisfy himself of the 

 existence of such excretory pores in the ordinary Ci/<lippe or Bcroi', although he has 

 repeatedly injected their whole alimentary canal ami its extensions, and has atten- 

 tively watcher! the currents produced by ciliary action in the interior of the bifurcat- 

 ing prolongations, which current^ always appear to him to return as from ciecal 

 extremities. He is himself inclined to believe that this arrangement, has reference 

 solely to tin nutrition of the nervous ganglion and tentacular apparatus, which lies 

 imbedded 'so to speak) in the bifurcation of (lie alimentary canal, so as to be able 

 to draw its supply of nutriment direct from that cavity. 



5 On the anatomy of BeroS, seeTSimex, Ziiologische Studien <u/f Cu/iri. T. Uebcr 



J3f-rni : lira/ nn, Leipzig, ]K7:i. 



