THORNELY— MARINE POLYZOA OF THE INDIAN OCEAN 155 



three denticles on the lower margin in place of the sinus. The dark membrane, 

 covering all but the rostra, some branched mandibles to the avicularia and the absence 

 of marginal spines all correspond with the description of this species rather than with 

 that of Holoporella tridenticulata (Busk) which it resembles. 

 Cargados, 28—30 fath. 



103. Holoporella tridenticulata (Busk), Report Challenger Exp., x, pt. xxx, p. 198. 

 There are the curious funnel-shaped processes distributed among the zooecia on these 



specimens. There are from 2 — 4 spines and the usual teeth on the lower margin of the 

 orifice, but they are not constant in being three, as sometimes one lateral tooth unites with 

 the central tooth making a sort of sinus to one side, sometimes the central tooth is missing 

 leaving a large, central sinus, and sometimes the margin is merely serrated. Aviculaina 

 are of two sorts, small on raised, suboral rostra and large, raised on tall processes, or 

 sunk between zooecia, and they may be long and dagger like or wide and fan like, the edge 

 of the beak often serrated. The operculum is either dark, or horn colour. Ooecia are 

 cucullate, having the granular surface of the zooecia. 



Salomon, 75 fath. ; Providence, 29 — 55 fath. 



104. Holoporella alhirostris (Smitt). (Busk), Report Challenger Exp., x, pt. xxx, 

 p. 193. 



Amirante, 12 — 18 fath. 



105. Holoporella mamillata (Busk). 



Cellepora mamillata, Busk, Brit. Mus. Cat., ii, p. 87. ' ' 



Amirante, 12 — 85 fath. 



There are large incrusting layers of this species. 



106. Holoporella foliata, MacGillivray. 



Cellepora foliata, MacGillivray, Prod. Zool. Vict. Dec. xvii, p. 246. 



This species is well represented in this collection. There are colonies measuring 

 2 inches by 2^ inches of a yellowish grey colour, growing from thick bases into flattened 

 hand-like branches which sometimes anastomose with other branches and are studded 

 over with jagged finger-like processes. 



Amirante, 29 fath.; Cargados, 30 fath.; Seychelles, 39 fath. 



107. Holoporella simplex (MacGillivray). 



Cellepora simplex, MacGillivray, Prod. Zool. Vict. Dec. xvii, p. 241. 



This is a large, coarse, brown species with large erect zocBcia, calcareous ridges running 

 often from one to another. One incrusting colony is half an inch thick and measures five 

 inches across, and has an irregularly mamillate surface, another IVom another locality is rather 

 smaller in its parts and grows into tubular branches. The oral and only avicularium 

 varies in size in the two colonifs, a little, it is more raised and the rostrum more raised 

 above it in the larger incrusting form. 



Amirante, 29 fath. ; Cargados, 30 fath. 



20—2 



