-70 MADREPOEARIA. 



42. Goniopora China Sea (5,3. (PL V. fig. 5; PL XIL fig. 9rt, %.) 

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



Descrijotion. — Corallum explanate, the first small circular colony forming the s]iecimen 

 was slif^htly convex. Later growths distorted, curled, and bent by foreign organisms. 



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

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

 "ranules expanding into flat, jagged, horizontal flakes. Wliere 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 ^\ ith 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, Imt not infrequently form a continuous ring with 

 radial thickenings or offshoots. 



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

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

 The coral is very light and appears friable. 



This 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 

 [ntroduction, 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. Ofi' 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 diff"erent 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 XXVII., " Astrccopora incrustans") 



a. Zool. Dept. 03. '.). 1. 12(;. 



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



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



Rkodarm gracilis, Bassett-Smith {non M.-E. & H.), Ann. and Mag. Nat. Hist. (6") vi. (1890) ]>. 4.37. 



Description.— Cor&Ybxm forms a stout almost columnar inverted cone, 14 cm. high, with 

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



