APPENDIX. 



SYSTEMATIC POSITION OF EOZOON. 



THE unsettled condition of the classification of the Protozoa, 

 and our absolute ignorance of the animal matter of Eozoon, 

 render it difficult to make any statement on this subject more 

 definite than the somewhat vague intimations given in the 

 text. My own views at present, based on the study of recent 

 and fossil forms, and of the writings of .Carpenter, Max 

 Schultze, Carter, Wallich, Haeckel, and Clarepede, may be 

 stated, though with some diffidence, as follows : 



I. The class Rhizopoda includes all the sarcodous animals 

 whose only external organs are pseudopodia, and is the lowest 

 class in the animal kingdom. Immediately above it are the 

 classes of the Sponges and of the flagellate and ciliate 

 Infusoria, which rise from it like two diverging branches. 



II. The group of Rhizopods, as thus defined, includes 

 three leading orders, which, in descending grade, are as 

 follows : 



(a) Lobosa, or Amoeboid Rhizopods, including those with 



distinct nucleus and pulsating vesicle, and thick 

 lobulate pseudopodia naked, or in membranous 

 coverings. 



(b) Radiolaria, or Polycistius and their allies, including those 



with thread-like pseudopodia, with or without 

 a nucleus, and with the skeleton, when present, 

 silicious. 



(c) ReLicularia, or Foraminifera and their allies, including 



those with thread-like and reticulating pseudo- 

 podia, with granular matter instead of a nucleus f 

 and with calcareous, membranous, or arenaceous 

 skeletons. 



The place of Eozoon will be in the lowest order, Reticularia. 



III. The order Reticularia may be farther divided into two 

 sub-orders, .as follows : 



