APPENDIX. 217 



would turn inside out the finger of a glove. This 

 oneness of cell and polype is a distinctive character 

 of the group. Another is the higher organization of 

 the internal parts. The mouth, surrounded by ten- 

 tacles, leads by gullet and gizzard through a channel 

 into a digesting stomach, from which the rejectable 

 matter passes upwards through an intestinal canal 

 till it is discharged near the mouth. The tentacles 

 also differ much from those of true Polypes. Instead 

 of being fleshy and contractile, they are rather stiff, 

 resembling spun glass, set on the sides with vibrating 

 cilia, which by their motion up one side and down 

 the other of each tentacle, produce a current which 

 impels their Hving food into the mouth. When these 

 tentacles are withdrawn, they are gathered up in a 

 bundle, like the stays of an umbrella. Our Plate I. 

 contains the following examples of Polyzoa. 



Valkeeia cuscuta. pi I. fig. 3. 



Prom a group in one of Mr. Lloyd's vases. Pig. 3 a 

 is the natural size of the central group of cells, in a 

 specimen coiled round a thread-like weed. Under- 



