484 TOPICS. 



BUB-SECTION III. 



The Echinoidea or Sea-urcliins as an Order. Ambulacral and interambulacral 



plates. Eyes. Deutal apparatus. Regular and Irregular Echinoids. 



SUB-SECTION IV. 

 The Asterioidea considered as an Order. Their form, structure, food, etc. 



SUB- SECTION V. 

 The Ophiurioidea considered as an Order. Astrophyton. 



SUB SECTION VI. 

 The Crmoidea The living and the lossil kinds. 



SECTION III. 



SUB SECTION I. 



The Acalephs considered as a Class. Meaning of the name. Size. Food. 



Classification. 



SUB-SECTION II. 

 The Cteuophoraj considered as an Order. Their form. Structure, etc. 



SUB-SECTION III. 



The Discophorte considered as an Order. Their form, structure, development, 



etc. 



SUB-SECTION IV. 



The Hydroidea considered as an Order. Their forms, modes of development, 



etc. " Fresh-water Polyps." 



SECTION IV. 



SUB-SECTION I. 



The Polypi considered as a Class. Their form and general structure. Lassos. 



Food. Modes of increase. Coral. Classification. 



SUB SECTION II. 

 The Alcyonaria considered as an Order. Leading forms. Spicules. 



SUB-SECTION III. 



The Actinaria considered as an Order. General absence of hard parts. The 



kinds which live in communities. 



SUB SECTION IV. 



The Madreporaria considered as an Order. The Principal forms. Coral Kecfa 



Coral Islands. Coral and limestone. 



