Coelenterata. 



and found that each locality has a size-mode of its own, due to environment, 

 e. g.j tropical forms are larger and coarser than Cape forms. There seem to 

 be within the limits of the species two distinct methods of growth, almost two 

 varieties, as well as the ordinary continuous and vegetative variations. The 

 anatomy of the soft parts of T 7 ., H., Ca. and Du. is very uniform. Nematocysts 

 occur in the endoderm towards the tops of the septa. 



T. Vaughan( 1 ) reviewing the literature of the simple genera of the Fungida, 

 arranges genera into families. Fungiidse - - Fungia. Agariciidse - - Trochoseris, 

 Palceoseris, Bathyactis, Fungiacyatlms. Micrabaciidse (n. fam. : simple Fungids 

 with solid septa and perforate wall) Micrabacia, Diafungia, Microsmilia, 

 Podoseris, Antilloseris (n. g. pro Turbinoseris eoccenica Duncan). Leptophylliidae 

 (n. nom. pro Ethmotidse Gregory) Gyroseris, Leptophyllia , Procydolites, 

 Haplar&a, Protethmos, Frechia, Physoseris (n. g. pro Trochosmilia insignis Duncan), 

 Lithoseris, Metethmos, Placoseris (Myriophyllia, Omphalophyllia, Craspedophyllia). 

 Anabraciida} - - Anabracia, Trochophlegma, Cyclolites, Trocharcea. The following 

 10 genera are not referred to families - - Phkgmatoseris, Mioroseris, Asteroseris, 

 Z/ittelofungia, Cyclabacia, Turbinoseris, Elliptoseris, Gonioseris, Epistreptophyllum 

 and Thecoseris. Stcphanoseris and Psammoseris and the Stephauophyllidse 

 (Stephanophyllum and Stephanophyllopsis) are wrongly referred to the Fungida. 



Duerden'/j iinds that under ordinary conditions the outer surface of coral 

 polyps is covered with a thin, continuous layer of mucus, in which objects 

 falling upon the polyp become embedded or entangled. When first extruded 

 the mucus is thin and watery but later becomes more consistent. From time 

 to time it is broken up into pieces which, along with any embedded foreign 

 particles, are driven from the surface of the disc by the ordinary exhalent 

 currents from the stomodajum. Nutritive substances and extractives placed 

 upon the polyp increase the amount of mucus exudated and also cause opening 

 of the mouth and the institution of an inhaleut stomodseal current by reversing 

 the dominant outward beat of thestornodseal cilia. The mucus exudated as a 

 result of nutritive stimuli is drawn down the stomodseum by inhalent currents 

 in the form of distinct streams carrying with it whatever substances, nutritive 

 or non-nutritive, are embedded or entangled in it. Ing estion in coral polyps 

 is thus purely mechanical depending on whatever substances are capable of 

 producing an inward beat of the cilia, opening of the mouth and exudation of 

 mucus. An inhalent current being established objects are carried into the 

 ccelenteron without regard to their nutritive value and independently of any 

 peristaltic motions on the part of the stomodseum. Mucus is of much im- 

 portance in the protection of the polypal surface from foreign objects, in keeping 

 it clean, and also in the entanglement and iugestion of prey and food substances. 



Duerden( 2 ) records the presence, in various species of Pocillopora from the 

 Hawaiian Islands, of invaginated tentacles, similar to those described by 

 Krempf (1904). They are found in about one in 12 of the polyps which 

 occur irregulary scattered over the colony. There are often 3 (never more), 

 sometimes 2 or 1, of these intrapolypal tentacles and they are found within 

 the dorsal directive entocoel and in the 2 neighbouring exoccels. The cellular 

 constituents of these modified tentacles are wholly endodermal but the cells are 

 much longer than those of ordinary endoderm and resemble the hypertrophied 

 endoderm cells found in the lower parts of the polypal cavity and like these 

 latter are probably non-active. Certain of the tentacles in P. and Seriatopora 

 were probably never formed as outgrowths but from the first grew inwards 

 into the ccelenteron, being influenced by mechanical causes, such as diminished 

 pressure, operating at that point. 



