416 Dr. F. Brliggemann on Stony Corals in 



lites arranged rather quincuncially (the oblique series being 

 most pronounced), distant by about the length of their dia- 

 meter, small, excessively short cylindrical (so as to appear 

 nearly immersed), slightly oblique, the opening directed 

 towards the edge of the leaf, the proximal part of the wall a 

 little more projecting. Cells open, very shallow. Septa 

 crowded, equal, generally 18-20 in number, narrow, with 

 straight inner edge, the lateral surfaces delicately spinulous. 

 Columella oviform, rather compact. Ccenenchyma mode- 

 rately dense, longitudinally striate and delicately echinulate 

 on the surface. Thickness of corallum, on the average, 3-4 

 millims. ; diam. of calicles 2 millims., their height | millim. 



Hab. Unrecorded. ~ B.M. 



This species is distinguished at the first glance by being 

 everywhere bifacial. In the other species there may be found 

 occasionally one or two calicles budding on the outer surface 

 of the corallum, or stout branches rising from the centre ; in 

 some of them, especially T. frondens and T. jpeltata^ there 

 occurs also a peculiar mode of plication, giving to the folded 

 parts the aspect of bifaciality. But in the latter instance 

 tliere is always a distinct suture on the ridges, separating two 

 well-marked rows of calicles, while nothing of this kind is 

 indicated in the present species. The corallites are in their 

 general aspect much like those of T. crater^ but less crowded, 

 smaller and more oblique. 



The single specimen seems to be only one half of the whole 

 corallum, which apparently formed a hemispherical cluster of 

 upright plates terminating at equal heights and obtusely 

 rounded at their summits. The plates scarcely coalesce wliere 

 they meet ; below they are united to a somewhat spreading 

 basal expansion. The height of the corallum is five inches ; 

 the greatest diameter, nearly eight inches. 



2. Astrceopora expansa. 



Corallum attached by a short pedicel, expanded, flat cra- 

 teriform ; under surface covered to the very edge with 

 a well-developed concentrically striate epitheca. Calicles 

 irregularly scattered, generally placed at great distances from 

 each other, small, rather deep, immersed, or with the margin 

 only slightly projecting. Septa unequal, 12 in number, quite 

 rudimentary in the upper half of the cell. Ccenenchyma 

 abundant, deposited in nearly continuous thin horizontal 

 layers, which are united by straight perpendicular trabeculse, so 

 that a vertical section shows a regular network, the square 

 interspaces of which are \ millim. in diameter. Surface 

 spongious and echinulate, rather scantily covered with very 



