CORALS FROM THE PERSIAN GTJLF, 10S9 



found in the Persian Gulf are closely related to species of corals 

 from the Tertiary deposits of Australia, and to a recent coral 

 found at depths of from 15 to 22 fathoms in St. Vincent Gulf,* and 

 iilentical with a recent coral from " no very great depth " in 

 Cook's Strait, New Zealand, 



Of the geogi-apical distribution of the other species very little need 

 be said. Heterocyathus heterocostatus is new, but a closeljr related 

 species H. cequicostafiis, of which one specimen was found, appears 

 to be widely disti-ibuted in the Indian Ocean. Paracyathus cavatus 

 is found in the Indian Ocean and is said by Alcock to be closely 

 related to the Eocene fossil F. crassus from the London Clay, 

 Agelecyathits persicus was previovisly recorded by Duncnn from 

 the Persian Gulf, but was said to occur also off St. Helena, 

 F ling ia patella occurs in the Indian Ocean, The type specimen 

 of Flahellum magnificum was found off Sumatra at a depth of 

 470 metres. The genera Ileieropsamnia and DenclrophyUia{i])'pQR.r 

 to be widely distributed in the Indian Ocean. So far then a,s 

 this small collection of corals is concerned, Pyrophyllia inflata is 

 the only species that even suggests a former connexion of the 

 Gulf with the Mediterranean Sea. 



The genus Pyrophyllia was briefly described in the " Manchester 

 Memoirs," 1910; but it may be convenient to take this 

 opportunity of adding a few general remarks on the genus and 

 of publishing some further illustrations (PI. LVII. figs. 8-1 1 ; 

 PI. LVIII. figs. 18, 19). 



Pyropliyllia infiata is a small unattached solitary coral, of 

 about 4 to 5 mm. in length, and 1 mm. in diameter at the margin 

 of the calyx. 



The two most important characters are : — (1) Its very 

 pronounced and- invariable octoradiate symmetry, and (2) the 

 presence on the external surface of well-marked accretion ridges 

 with short but definite costal spines (text-fig. 221). 



Pyrophyllia is related to the recent genus Guynia, and 

 to the extinct Tertiary genus Conosmilia. The number of 

 septa in Pyrophyllia and in Guynia is sixteen, and of these eight 

 are larger and may be called the'primary septa, and the remaining 

 eight are smaller and may be called the secondary septa. 



In Guynia one of the eight primary septa is larger than 

 the others, this large septum being according to Duncan a 

 " very marked rugose peculiarity." Moreover, in Guynia four of 

 the primary septa are sometimes larger than the other four, so 

 that according to Duncan the system of septa is four primary 

 septa, four secondary septa, and eight tertiary septa. 



In these respects and in others of less importance, Guynia 

 seems to be distinct from Pyrophyllia. In the genus Conosmilia 

 there is a more variable arrangement of the septa. In 

 C. elegans, C lituolics, and 0. anomala there are eight 

 primary septa, eight secondary septa, and thirty-two tevtmvj 



* The specimens of this coral T, verconis were much worn fvud were no doubt 

 dead corals when collected. 



