476 ACALEPHJE ; CYDIPPE. 



freely swimming through the water, it is always widely dilated. 

 From the stomach, there passes a narrow straight intestine, which 

 terminates at the opposite extremity of the body. When the 

 animal is in active movement, therefore, a continual stream of 

 fluid will enter its mouth, and will pass out again behind ; and 

 from the minute particles contained in this fluid, its nourishment 

 is probably in part derived. 



1036. These apparently powerless little animals feed, however, 

 like other Acalephas, upon species of much higher organisation 

 and firmer texture ; and they are provided with similar means 

 of obtaining them. From the posterior part of the body arise 

 two filaments, which are many times its own length. These are 

 provided with lateral filaments, which arise at regular intervals 

 from one side along their whole course, and are spirally coiled 

 like the tendrils of a pea. The principal filaments do not arise 

 from the surface of the body, however, but from the bottom of 

 two deep cavities extending into its interior. Into these cavities 

 the main filaments with their appendages can be entirely retracted. 

 The lateral fibrils seem to contract spirally towards the longitudinal 

 filaments ; and the latter are drawn by irregular contractions 

 into the cavity, so as to be entirely concealed. When the animal 

 wishes to put them forth, it seems to contract the cavity, and the 

 filaments are jerked forth, as it were, not simultaneously, but 

 first on one side and then on the other. When the main fila- 

 ments have been ejected from the body, the little tendrils begin 

 to uncoil. When one of these beautiful little animals is placed 

 in a vessel of sea- water, it sometimes remains at the bottom, 

 projecting its long filaments upwards. At other times it darts 

 upwards with great velocity, drawing its long filaments after it, 

 retracting and extending them alternately. Not unfrequently it 

 remains for some time at the top of the water ; and, when it 

 wishes to descend, it turns over, drawing up its filaments sud- 

 denly, and then swims, mouth-downwards, to the bottom of the 



1037. The Cesium Vmeris, or Girdle of Venus, an Acalepha 

 belonging to the same group with the preceding, is a flat riband- 

 shaped animal, which sometimes attains the length of five or six 



