26 A Guide to the Zoological Collections in the 



integument the stony protection and support known as 

 "coral." The coral, or " corallum," when freed from the 

 soft parts of the animal by maceration (as is done in most 

 Museum specimens) consists of an outer cup or " calice," 

 which usually contains a central upstanding column or 

 "columella " and numerous series of vertical plates radia- 

 ting from the columella to the calice wall — the *'sklero- 

 septa" and " pali " — by w^hich the mouth and tentacles 

 are supported. The vertical section through the corallum 

 of Caryophyllia communis in Case 16 shows this well. 



The living Madreporaria are divided into three sections 

 — the (i) Madreporaria Aporosa, (2) Madreporaria Fun- 

 gida^ and (3) Madreporaria Perforata. 



MADREPORARIA APOROSA. 



[(Eas^s 14-16]. 



In the Madreporaria Aporosa the corallum has a solid 

 wall and solid septa. This section is divided into four 

 families — the Turbinolidx, the Oculinidie, the Pocillopori- 

 dse, and the Astr^idx. 



ist Family Turbinolidas— In which the corallum is almost 

 always a single simple calice or cup, with the chambers 

 between the sklero-septa (" interseptai loculi ") open to 

 the bottom of the cup. Branching colonies never occur 

 and the Turbinolidge therefore play no part in the forma- 

 tion of coral reefs. 



Many of the Turbinolidx live at the bottom of the deep 

 sea, where sometimes, as in the case of Caryophyllia cotn- 

 munis, they occur in large beds. This family is represent- 

 ed in Case 16 by the following genera, all of which occur in 

 Indian waters : — Flabellum, Rhizotrochus, Deltocyathus, 

 Paracyathus^ Heterocyathus, Caryophyllia^ Stephano- 

 trochus, Discotrochus, and Poiycyathus, the latter being 

 one of the very few Turbinolians that form colonies. 



