4 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 16 



It appears highly probable that an expedition which was primarily con- 

 cerned with collecting corals would bring in much more material, both 

 in quantity and in variety. The numerous species and genera which are 

 represented by single specimens are probably not indications of the 

 paucity of the coral fauna, but rather indications of the lack of proper 

 collecting. 



The occurrence of the Caribbean genus Agaricia is anomalous, and 

 because of this, the small poorly preserved specimen has been carefully 

 scrutinized to see if it is possible to refer it to some other genus. Its 

 occurrence in the Panamic region should be verified by additional work, 

 but close relationships with the Caribbean fauna are indicated by the 

 occurrence of Madracis asperula and Cladocora debilis in both areas. 

 Similarly the occurrence of species of the genera Phyllangia, Lophelia, 

 Thecopsammia and Solenastrea in the two regions indicates past inter- 

 communication. In view of the occurrence of the genera Dichocoenia, 

 Diploria, Eus?nilia, and Siderastrea in the lower Pliocene of the Gulf 

 of California (Durham, 1947, p. 14), it is not improbable that they may 

 eventually be found living in the Eastern Pacific. Eusmiiia and Sider- 

 astrea are also known in the earlier Tertiary of the Pacific Coast Region 

 (Durham, 1947, p. 7). 



The large number of species of the genus Astrangia recognized, raises 

 some doubt as to the validity of the specific criteria used in determining 

 them. For this reason they should be restudied when more material is 

 available. However, it is to be noted that all of the specimens from any 

 single locality appear to be moderately restricted in the individual varia- 

 tion present, thus tending to confirm the limited specific variation recog- 

 nized. In explanation of the large number of species it may be suggested 

 that possibly conditions in the Eastern Pacific are highly favorable to this 

 genus, and that the planulae may have a very short motile stage, with 

 the consequent development of numerous local endemic species. 



Despite the fact that 13 of the species here listed from the Galapagos 

 Islands have not been recorded elsewhere in the Eastern Pacific, there is 

 little known about the fauna to indicate any great degree of isolation. 

 These 13 species include representatives of the genera Astrangia, Bal- 

 anophyllia, Desmophyllum, Flabellum, Kionotrochus, Lophosmilia, Mad- 

 racis, Madrepora, Pavona, and Thecopsam7nia. Of the preceding, it is 

 only the species of the genus Kionotrochus that might be significant ; it 

 has been recorded from several localities in the islands but not elsewhere 

 in the Hancock collections. The species of Madracis seems to be identical 

 with Madracis asperula of the Caribbean, while the remaining species 

 are usually known from but a single locality and thus probably have 

 no significance. 



