96 



INVEUTRBKATE ANIMALS. 



cilia there are two very long and flexible tentacular i)rocesse3, which 

 are fringed on one side ]<y smaller secondary branches. The ten- 

 tacles arise each from a kind of sac, one ])laced on each side of the 

 body, and they can be instantanecjusly and comjiletely retracted 

 within these sacs at the will of the animal. The mouth of I'li/iirn- 

 hrachia opens into a spindle-shaped digestive sac or stomach, wliicli 

 in turn opens below into a wider and shorter cavity termed the 

 "funnel"; from this there proceed in the axis of the body two 

 small canals, which open at the opposite pole of the body. The 

 fmmel communicates with a complicated system of canals, which 

 ai'e ciliated internally, and are filled with a nutrient fluid. In the 

 angle between the two canals wdiich run from the base of the 

 funnel to the surface is a little vesicle or sac, believed to be a 

 rudimentary organ of hearing, and placed upon this is a little mass 

 which is generally believed to be of a nervous nature. The repro- 

 ductive organs are develojjed in the walls of the canal-system. 



Fio- ri!!.— Oteuophura. C^^Ufui Vciii'vi^, reduced in Kize. 



The oidy other f<irm of the CfiiKiji/iiira which deserves mention is 

 the "Venus's girdle" {Crxtinn Ycin-rix), wliich agrees in essentials 

 with Plijiirnhrar/ii'a, but is greatly elongated in a direction at right 

 angles to the alimentary canal, till we have a ribljon-shaped body 

 j)i-odaced (fig. 5!)), four or five feet in length and two or three inches 

 high. Cextiim is not uncommon in the Mediterranean, and has the 

 jiowerof phosphorescence, ajii)earing at night as a mcjving and twist- 

 ing band of flame. 



