1899.] ASTEJEID COEA.LS T'EOM 1?HE SOUTH PACIFIC. 74S 



growing on the lagoon-shoals at Funafuti ; I did not, however, 

 find it ever on the reef itself in that locality. In Fiji it is very 

 common, gro\ving at AVakaya both in the lagoon and on the 

 leeward reefs. 



The monticules of the Funafuti specimens are about 2*5 mm. 

 distant from one another and 2 mm. high. On a Wakayan 

 specimen from the lagoon they are 3-3'5 mm. distant and 2*5- 

 3 mm. high, and on one from the reef 3-4*5 mm. distant and 

 3-4 mm. high. The differences between the latter specimen and 

 the Funafuti specimens are so striking that at first sight they 

 would appear to belong to distinct species. The variations are 

 probably, however, due to absence of sand and mud, together with 

 a more abundant food-supply on the reef at Wakaya. The lagoon- 

 shoals of Funafuti are but sparingly covered with corals, whereas 

 the whole reef to leeward of Wakaya is in many places covered 

 with very luxuriantly-growing Madreporaria, Millepora, Heliopora, 

 and Tidiipora to within about 15 yards of the breakers. 



The species forms large hemispherical masses, which commonly, 

 as in Porites, die in the centre and are hollowed out, continuing 

 to grow at the periphery. The monticules of the upper surface 

 of an overhanging mass are somewhat pointed, while chose of the 

 lower surface are often flattened and very massive. 



Funafuti; Wakaya, Fiji ; Rotuma (spirit-specimens only). 



2. HYDifOPHORA LOBATA Lamarck. (Plate XLVIII. fig. 2.) 

 Monticularia lobata, Lamarck, Hist, des Anim. s. Vert. ii. 



p. 250 (1816). 



Hydnophora lohata, Milne-Edwards & Haime, Cor. ii. p. 421 

 (1860). 



One small specimen, which corresponds fairly well with the 

 descriptions. It is a bifid lobe apparently torn off fx-om a large 

 massive colony. The monticules vary up to 7 mm. in length, and 

 are from 2-5 to 5 mm. distant from one another and 3-5 mm. high. 

 On the opposite sides of the valleys thick and broad septa 

 alternate with thin and narrow. The broad septa apparently 

 bifurcate and meet one another, fusing in the centre of the 

 valleys ; the large septa of one monticule lie then opposite to the 

 small septa of the neighbouring monticules. The sides of the 

 septa are granular and their edges are entire, save that the large 

 septa have conspicuous vertical teeth where they bifurcate. The 

 interseptal loculi vary up to 8 mm. in depth, and are closed below 

 by horizontal partitions of endotheca. 



Funafuti ; 20 fathoms outside the reef. 



3. Hydnophoka exesa Pallas. (Plate XLVIII. fig. 3.) 



Madrepora exesa, Pallas, Elench. Zooph. p. 290 (1766). 



Hydnophora demidovii, Fischer, Mus. Demidoff, iii. p. 295, pi. iv. 

 (1818). 



Monticularia polygonata, Lamarck, Hist, des Anim. s. Vert, ii, 

 p. 250 (1816). 



