126 PAPERS FROM THE DEPARTMENT OF MARINE BIOLOGY. 



Dana's type, from the Fiji Islands, is in the U. S. National Museum, No. 35, 

 and there are 3 other specimens from Hereheretue, Paumotus. As the specimen 

 from Murray Island differs from the type and other typical specimens, it will be 

 described as follows: 



Corallum an incrusting, subquadrangular plate, about 13 cm. wide, 15 cm. long, and 

 3 cm. thick in the center, thinner on the edge. 



Corallite walls fused, solid, about 3 mm. thick. 



Calices polygonal, subelliptical, orsuboval. Lesser diameter 9 to 13 mm.; greater, up 

 to 17.5 mm., 15 mm. usual. Depth, 6 or 7 mm. 



Septa thickened in the walls, directly continuous between adjacent calices, or ends 

 separated by an obscure groove. Narrow above, sloping steeply to near level of columella, 

 where they widen. Number in a calice 13 by 15 mm. in diameter, 20 reach the columella, 

 about 17 project half-way or farther to the columella, 6 shorter septa, total number 43. 

 Outer ends of all septa subequal in thickness, there being no regular alternation in size. 

 Inner parts thin. Members of higher cycles frequently fuse to the sides of those of the lower, 

 forming groups of 3 to 5 septa. 



Septal margins, spinose on and near the wall, spines slender, up to 1.5 mm. long. Usu- 

 ally a spine on the top of the wall, or one on each side of the top, with one or two prominent 

 spines near the top of each septal edge within the calice; the lower dentations serrate, less 

 prominent, often a slight increase in length near the columella. There are no definite 

 paliform lobes. Septaf faces smooth or nearly smooth, granulations when present small and 

 scattered. 



Columella small, poorly developed, trabecular, only about one-fifth the diameter of 

 that of a calice. 



Reproduction by subequal fission, a wall forming across and separating two polypite 

 centers. 



Station, Murray Island. — Lithothamnion ridge. 



Matthai 1 places Astrea dipsacca Lam., Acanthastrea hirsuta, spinosa, brevis, and 

 grandis of Milne Edwards and Haime, and Acanthastrea irregularis Quelch in the 

 synonymy of Favia {Acanthastrea) hirsuta (M. Edw. and H.). Acanthastrea echinata 

 Dana differs from Matthai's description chiefly in having the sides of the septa 

 closely granulate, and in usually having the septa of adjacent calices continuous 

 across the wall. In these characters the specimens from the Paumotus accord with 

 Dana's type. The figures published by Matthai (plate 24, figs. 7, 8) show septa 

 usually continuous across the wall, but do not show the character of the septal 

 faces. I doubt the last-mentioned character being of specific value, as it is evi- 

 dently variable. Therefore, should Audouin's name dipsacca not have been intended 

 to apply to this species, Dana's name echinata would be the proper one. 



Distribution.— Red Sea; Maldives; Murray Island; Tongatabu; Fiji Islands; 



Paumotus. 



GENUS NOT REFERRED TO ANY FAMILY. 



Genus MERULINA Ehrenberg. 

 1834. Merulina Ehrenberg, Corallenth. Roth. Meer., p. 104. 



Type species: Madrepora ampliata Ellis and Solander. 



Dana referred 8 species to Merulina, as follows: 71/. ampliata (Ell. and Sol.), 

 M. regalis Dana, M. speciosa Dana, M. crispa Dana, M. folium (Lam.), 71/. scabri- 

 cula Dana, M. laxa Dana, and 71/. rigida Dana. His types or original speci- 

 mens for all of them, except M. folium, are in the U. S. National Museum. All 

 the species except 71/. folium and 71/. rigida, which belong to Hydnophora, are still 

 retained in the genus. M. folium is a synonym of H. exesa (Pallas), while 71/. rigida 

 is considered a valid species. 



'Trans. Linn. Soc. London, 2d. ser., Zool., vol. 17, pp. 100-102, 1914. 



