458 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1963 



tion. For example, the Scotia Arc undoubtedly was once more con- 

 tinuous than at present. Because the influence of such a continuous 

 structure upon the faunas must have been great, a study of the faunal 

 continuity may give us information on the "how" and "when" of such 

 connections. 



But aside from such broad-scale regional studies, what values are 

 there in the study of the Antarctic corals ? One of the most important 

 features of the coral fauna of the Southern Ocean is the availability of 

 large numbers of individuals of one species, making possible studies 

 of intraspecific behavior and ecological relationships rather than only 

 the broad application of ecology to a faunule. We are therefore able 

 to phrase such questions as: How does the form of an individual coral 

 vary in response to the local differences in environment? What are 

 the mechanisms by which the animal adapts to these local changes? 

 How do these animals which possess only a rudimentary nervous system 

 (members of the Coelenterata, the group which includes the corals, 

 have the most primitive nervous systems of the animal kingdom ) orient 

 themselves and sense the environment? These questions could be an- 

 swered to some degree on other corals in other places. Eeef corals 

 are very accessible and satisfactory for certain types of physiological 

 experimentation. Shallow-water occurrences of solitary corals are 

 now being utilized for experimental studies in temperate and tropical 

 regions. But these latter are essentially the studies of individuals 

 and of individual reactions, and colonies give only a summation of the 

 collective response through time. The large popul ations of individuals 

 of a single species to bo found in the Southern Ocean permit studies 

 of population response and behavior, on a statistical basis. 



Among the questions being studied are : How does the animal react 

 to the unfavorable cold climate in the secretion of calcium carbonate? 

 What mechanisms are involved in the protection of the skeleton from 

 the effects of the environment and from predators ? In progress are 

 studies of the way a coral reacts to the instability of its environment, 

 as in the instance of the coral which attaches to a pebble. Wliile the 

 coral is small, the pebble is proportionately large in mass, but as the 

 coral grows, the pebble becomes proportionately smaller and smaller 

 in respect to the coral until it does not afford the stability that it once 

 did. Some species apparently do not "care" and continue to live quite 

 successfully even after they have fallen over ; others do not thrive in 

 a prone position and deposit a variety of structures and roots to better 

 secure themselves in their environment. Once some of the basic ques- 

 tions involved in this sort of performance are answered, such as (1) 

 How does the coral (lacking sense organs as we generally think of 

 them) know it is not vertically aligned ? (2) How does the coral know 

 where and what type of roots or supporting sti*uctures to form? (3) 

 How do the larvae know what size pebble to select before settling? 



