226 CLASSIFICATION OP THE ANIMAI, KINGDOIk^. 



Gastrula stage. It is conceivable that an opaliniform Morula 

 should, under completely parasitic conditions of life, have deve- 

 loped the organization of a Cestoid worm. At any rate, the con- 

 trary must not be assumed without good evidence ; and to indi- 

 cate the doubt, it may be well to establish a provisional group of 

 AgastresB for these forms. 



I subjoin a tabular arrangement of the animal kingdom accord- 

 ing to the views expressed in this paper, remarking, in conclusion, 

 that, in my belief, the progress of knowledge will eventually break 

 down all sharp demarcations, and substitute series for divisions, 



ANIMALIA. 

 I. PBOTOZOA. 



i. MONEEA. 



Protamcebid(je. ProtoyiionadidcB. Myxastridod. Foraminifera. 

 ii. Endoplastica. 



AmoebidcB. Infusoria Jlagellata. G-regarinidae. Acinetidcs. 

 Infusoria ciliata. Radiolaria. 



II. METAZOA. 



A. GrASTEE^. 



i. POLTSTOMATA. 



Porifera (or Spongida). 



ii. MONOSTOMATA. 



1. Archaeostomata. 



a. Scolecimorpha. b. Ccelenterata. 



Motifera. Turiellaria. Hydrozoa. 



Trematoda. Actinozoa. 



Nematoidea. Ilirudinea, {Otenopliord) . 



Oligoehceta. 



2. Deuterostomata. 



a. Schizoccela. h. Enteroeoela. 

 f ^ , , ^ ^ , 



Annelida Gephyrea(y). Brachiopoda. Enteropneusta, 



polycTiceta. Polyzoa (?). Chcstognatha, 



Arthropoda. Mollusca. Echinodermata. 



c. Epicoela. 

 Tunicata or Ascidioida. 

 Yertebrata. 

 B. Agastre^ (provisionally). 

 Cestoidea. Acanthocephala. 



