VAUGHAN: MADRErOIlARIA. 69 



The upper surface is occupied by short erect branches, which are conical in shape 

 in the central portion. One of the central branches is 14 mm. in diameter at the 

 base, and 14 mm. in lieight. Outside tlie central area, as the wall of the vase slopes 

 rather steeply, the outer angle between a branch and the branch from whicli it rises 

 or the common wall, is acute. The maximum length of the free portion of a branch 

 is 27 mm. ; the branches are radially compressed, diameter along a radius 12 mm. 

 (a little more than 1 cm.), perpendicular to a radius 1 cm. or slightly less. Apices 

 from 1 to 2 cm. apart. Nearly all the branches bear branchlets or proliferous 

 calices. 



Calices on the expansion below the pedicel immersed, from the base of the pedi- 

 cel to the upper edge the immersed calices become progressively fewer, while 

 slightl}' protuberant ones become more numerous. Apertures labellate or circular ; 

 the inner wall may or may not be elevated. The maximum height of these ex- 

 ternal corallites is about 2 mm. ; diameter of base about 2 mm. ; calicular diame- 

 ter about 2 mm. ; diameter of aperture about .75 mm. The corallites decrease iu 

 diameter toward the calices very slightly. Corallite wall costate, perforate. The 

 corallites of the upper surface are immersed between the bases of the branches, 

 about 1 mm. in diameter; on the branches there are immersed corallites, the other 

 corallites may be labellate with only the outer wall developed, nariform or tall and 

 proliferous. The diameter of the calicular aperture is about .75 mm., one of the 

 long corallites is 3.5 mm. in length. The apical corallites are frequently aborted, 

 when present, 1.75 mm. is probably an average diameter, projecting about 1 mm. 

 The corallite walls are acutely costate, and often imperforate except near the upper 

 edge. 



Two cycles of septa are uniformly well developed, the directives more pro- 

 nounced. 



Coenenchyma echinulately striate, perforate, but with a tendency to compactness. 



Locality : — Manga Reva. 



Remarks : — I do not know of any other species that closely resembles this 

 one ; there is a superficial resemblance to all other vasiform, or palmate 

 Acroporae, but there the resemblance, so far as my knowledge goes, stops. 



Acropora diomedeae, sp. nov. 



Plate 7, Figs. 1,1a; Plate 8, Figs. 2, 3. 



Corallum vasiform, with a pedicellate base. The branches fusing completely 

 except near the periphery. 



Height, 20.7 cm. ; diameter of vase, 32 cm. 



The upper surface is occupied by short erect, or sub-erect branches that rise 

 from a common plateau. They are irregular in height and diameter, between 3 

 and 3.5 cm. tall near the periphery, and 8 ram. in diameter at the base ; at the center 

 the height is about 2.6 cm., diameter at base may be as little as 7 mm. The dis- 

 tance apart of the bases is usually less than 1 cm., 6 to 8 mm. Very few of the 

 branches are single, finger-like processes, most of them bear less developed lateral 

 branchlets or proliferous calices. 



Calices of the lower surface immersed near the lower edge of the pedicel ; some, but 

 a very few, are immersed on the bowl portion of the vase. The other calices slightly 

 elevated, appressed, with distally directed, circular apertures. The corallites are 



