the food origin, there are outside and inside consumers. Outside consumers 

 feed on the water mass organisms or particles (sea-fans, corals, ophiurids, 

 ascidians, young Thalassoma .,, etc.) or on the benthic fauna of the neighbor- 

 hood ( Holocentrus , Balistes , moray) . Inside constomers feed on the microcosm. 

 They are algae browsers or omnivores (damself ishes, blennies) , microcarnivores 

 (polychaetes, crabs), detritivores (polychaetes) . So the greatest consumers 

 are the outside ones. The effect of the foraging foreigners seems to be lim- 

 ited. Only two S err anus tabaricus , one Canthigaster and a young parrotfish 

 have been sporadically seen. This danger seems to be checked by the microcosm 

 inhabitants; for instance, a parrotfish which wanted to browse on the block 

 was pushed away by the squirrelf ish. 



A summary of the observed activity patterns of behavior observed is shown in 

 Tables 2, 3, and 4. 



Table 2. Activity pattern of sessile fauna found in the study area. 

 Species 



Sponges 



4 different species 

 Corals 



Activity 

 Pattern 



Comments 



(dN?) 



Montastrea annularis 

 Eusmilia fastigiata 

 Montastrea cavernosa 

 Meandrina meandrites 

 Porites astreoides 

 Sidastrea radians 

 Astrangidae 



Sea-Fans 



The last two are in crevices 

 of the block, the others on 

 the sides or on the top of it. 



Pseudopterogorgia americana 



Eunicea calycul ata 



Ascidians 



A pedunculate species 



sp. 1 



sp. 2 and sp. 3 - Didemnids 



(G) 



(C) 



(dN) 

 (dN) 



A 35 cm high speciment at the 

 top of the block. 



A large specimen, 90 cm high, 

 growing obliquely on the low- 

 est part of the west side. 



VI-290 



