APPENDIX. 



PLATE I. 



ZOOPHYTA. POLYZOA. 



The forms of animal life which are now united in 

 an independent class, under the name Polyzoa, so 

 nearly resemble the Hydroid Zoophytes in general 

 form and appearance that a casual observer may sup- 

 pose them to be nearly identical. In all but the more 

 recent works, they are treated as distinct indeed, but 

 still included under the general term " Zoophytes." 

 The animals of both groups are minute, polypiform 

 creatures, mostly living in transparent cells, springing 

 from the sides of a stem which unites a number of 



