1899.] ASTR^IB COEALS FEOM THE SOUTH PACIFIC. 759 



specimen agrees closely witb the form described by Milne-Edwards 

 and Haiine under the name of P. jyrofundiceUa. A third specimen 

 (e) conforms closely over the greater part of its surface with Dana's 

 figures and descriptions of F. vhens, with which the polyps of 

 all agree in colour. The young calices, however, and those 

 situated near the edges of the colony are precisely similar to calices 

 in the same situation in specimen {a). 



Prom the above it would appear that P. profundicella and 

 P. virens can only be synonyms for different facies of P. ahdita. 

 It would also seem probable that several other species, described 

 by various authors, are likewise synonyms, 



Rotuma ; crest of reef. 



2. Pb,io]S"aste.ea fusco-vibidis Q. & Gr. (Plate XL VII. fig. 5.) 



Astrcea fiisco-viridis, Quoy & Gaimard, Voy. de I'Astrol. iv. 

 pi. xvh. fig. 8 (1833). 



Astrcea fusco-viridis, Dana, Zooph. p. 229, pi. xi. fig. 7 (1848). 



Prionasti'cea fusco-viridis, Milne-Edwards & Haime, Cor. ii. 

 p. 523 (1857). 



I have referred two incrusting masses to this species because 

 the polyps agree absolutely in colour with the above descriptions. 

 The species, too, has priority over the species described by 

 Ehrenberg, Milne-Edwards & Hairae, and Dana, with several of 

 which the corallum conforms equall}^ well so far as the descriptions 

 and figures go. 



The peristome of the polyps is of a bright green colour, rouud 

 vi'hich the estei'nal body-w^all forms a broad brown ring. The 

 calices vary in shape and depth in dijferent parts of the corallum, 

 but the dividing walls are always relatively thick, compact, and 

 triangular in section. The septa are continuous from calice to 

 calice, and are from "5-1 mm. exsert. They vary in number, in 

 the largest calices (1*4 cm. in diameter) often as many as 70 being 

 counted, of \Yhich about 25 are subequal in size and fuse wi*h the 

 columella. These alternate with a similar number, which project 

 about half as far, and then there are a number of very narrow 

 septa, in calices of about 1 cm. diameter, scarcely recognizable. 

 All the septa except the smallest are very thin, regular, and 

 equally exsert. Their edges are covered with small, subequal, 

 bluntly angular teeth, usually very close-set, and never have a 

 ragged appearance. In some of the shallower, thicker- walled 

 calices the teeth are often broader, and the section may have an 

 almost precisely similar appearance to that given by Dana in 

 pi. xi. fig. 7 c. The columella is usually well marked and compact, 

 being formed by an anastomosing mass of thintrabeculae, generallf 

 ending above in fine papillse. 



Eotuma ; the species is very common, living on the extreme 

 breaking edge of the reef. Similarly coloured species to this and 

 P. ahdita were also very common in the same position on the reefs 

 of Wakaya, Piji. 



49* 



