MADREPOEARIA. 



42. Goniopora China Sea (6) 3. (PI. V. fig. 5 ; PL XII. fig. 9a, %.) 

 [Macclesfield Bank, 28 fathoms, coll. Bassett-Smith ; British Museum.] 



Description. — Corallum explanate, the first small circular colony forming the specimen 

 was slightly convex. Later growths distorted, curled, and bent by foreign organisms. 



Calicles 2-3 mm. across, nearly flush with the surface. Walls here distinct, being very 

 slightly but somewhat sharply raised, there almost flush. In the former case built of irregular 

 granules expanding into flat, jagged, horizontal flakes. Where flush these flakes run with 

 nearly smooth surfaces (except for small sparse granules), but with ragged edges into the 

 calicle. The septa are quite irregularly shaped out of these wall flakes, or out of those of a 

 lower layer, or appear as small knobs from between the layers ; parts of the typical formula, 

 even with its fusions, can be seen here and there ; radial symmetry greatly obscured, so that at 

 times the calicles are hardly recognisable at all. From the irregular flakes forming the colu- 

 mellar tangle groups of granules arise, most prominent in those calicles in which the walls 

 are prominent. They are very irregular, but not infrequently form a continuous ring with 

 radial thickenings or offshoots. 



In section the texture is a light large-meshed reticulum, in which the horizontal elements 

 •are flaky and more conspicuous than the vertical ; vertical continuous trabecular are absent. 

 The coral is very light and appears friable. 



Tliis striking modification of the typical skeleton, due to the development of its 

 horizontal elements at the expense of its vertical, is rendered the more remarkable because 

 there is a Porites from the same place with the same modification (see next volume, also 

 Introduction, p. 20). 



This remarkable resemblance between corals of two different genera in the same locality 

 is not the only case I have discovered of this kind. Off the Amirantes there are Montipores 

 and Porites (which will be described in Vol. V.) almost exactly resembling one another. 



The single specimen has been distorted by Annelids, Balanids, and a large calcareous 

 algal concretion. The different calicles described above are on different slopes of the surface, 

 perhaps showing therein the influence of position on structure. (Cf. the two sides of the 

 same specimen shown in Vol. II. Plate XXVIL, " Astrceopora incrustans.") 



a. Zool. Dept. 93. 9. 1. 126. 



43. Goniopora China Sea (5) 4. (PL V. fig. 6 ; PL XII. fig. 10.) 



[S. side of Itu Aba, Tizard Bank, 2 fathoms, coll. Bassett-Smith ; British Museum.] 



Rhodarcm gracilis, Bassett-Smith (non M.-E. & H.), Ann. and Mag. Nat. Hist. (6°) vi. (1890) p. 457. 



Description. — Corallum forms a stout almost columnar inverted cone, 14 cm. high, with 

 smooth flattened convex top, 12 by 8 cm., and appearing as if built up of layers, owing to the 



