I. INTRODUCTION, 



The present paper forms the first part of an account of a 

 remarkably fine collection of corals from the Cape of Good 

 Hope, entrusted to me for identification. Most of the specimens 

 appear to have been preserved in formalin, an excellent re- 

 agent, but one which is somewhat uncertain in its results. To 

 give an instance, corals of the genus Flabellum are almost 

 uniformly well preserved, while those of Caryophyllia are 

 almost useless for anatomy. In any case the examination of 

 more than the gross anatomy of the polyps of the various 

 species, or forms, in the different genera is not, in view of the 

 results obtained in the present genus, particularly to be 

 desired. 



The collection is of peculiar interest from the fact that the 

 same forms have been repeatedly dredged in slightly or 

 considerably different localities. Thus the variation due to 

 different habitats may subsequently be worked out, and corre- 

 lated perhaps with the physical and other conditions. For 

 this purpose accurate charts for each locality of the tempera- 

 ture of the sea, of the character of the bottom, and of the 

 currents both on the surface and to the bottom are desirable, 

 as well as a knowledge of the topography and the fauna and 

 flora. The present and further collections will give a correct 

 knowledge of the " normal '^ or " continuous " variations in 

 each species, and it may be hoped that the presence and 

 nature of "discontinuous" or "specific" variation in the 

 group may be elucidated. At the same time the accurate 

 knowledge of the coral fauna in anyone locality /// relation la 

 lis environment must necessarily be of immense value in 

 deducing the conditions under which tertiary and earlier 

 coralline deposits have been formed, in effect in studying the 

 history and geography of the earth.* 



Most workers on the systematic side complain of the 

 enormous difficulty of determining the species of corals. This- 

 seems to me to be more apparent than real. It has probably 

 arisen largely owing to the not-unnatural desire to refer each 

 specimen to a species — to give each a convenient handle by 



* The above paragraph was written before I received the ''Report of the 

 Government Biologist for the Year iqoo." I find therein most or all the informa- 

 tion I desire as to the environment, i:)hysical conditions, etc. 



A27o4. B 



