CORALS FROM THE CORAL RAG. 89 



swellings of the walls. As to Lithodendron suhdicliotomum} Calamophyllia simplex^ and 

 C. Bernardana,^ and Lithodendron Moreausiacum ,^ which we are inclined to refer to the 

 same genus, we are not sufficiently well acquainted with them to be able to point out their 

 characteristic features. 



Genus Calamophyllia, (p. xxxiii.) 



Calamophyllia Stokesi. Plate XVI, figs. 1, \a, \h, \c. Id. 



Corallum composite, fasciculate, and composed of very tall subcylindrical or sub- 

 prismatic corallites, which present a considerable number of annular expansions. These 

 circular ridges are placed at a short distance from each other, and appear to be formed 

 by the inferior edge of a series of laminae lapping over each other. The corallites 

 dichotomise at short distances, and under very acute angles; the new branches thus formed 

 continue ascending parallel to each other, and are in general somewhat constricted 

 immediately above the point of origin. The costce are quite straight, very delicate, and 

 closely set, but separated by deep, well-marked, narrow furrows; they do not project much, 

 and are composed of a series of granulations more or less confounded together (fig. \ci). 

 In general they are all nearly of the same size ; but in some parts they are alternately a 

 little thicker. The form of the calice is somewhat irregular (fig. \c, \d, \e); it is seldom 

 quite circular, and usually more or less oval or subpolygonal. The fossula is shallow, the 

 columella null or rudimentary, and the septa numerous ; in the large calices there are about 

 seventy of these radiate laminse, and we must, therefore, suppose that there are four 

 complete cycla and a fifth cyclum incomplete ; but it is very difficult to distinguish the 

 different systems, and there exists, in all probabiUty, much irregularity in their mode of 

 growth. The sepAa are very thin, broad, closely set, and exsert; their upper edge is 

 slightly arched and regularly crenulated (fig. l*^), their sides granulated. Those of the 

 first three cycla differ but little, and those of the fourth cyclum are also highly developed ; 

 but those of the fifth cyclum are much smaller. A vertical section of one of these corallites 

 shows that the laminae which form the septa are very cribrate, and by means of a horizontal 

 section numerous small dissepiments are exposed to view ; thgre are seven or eight of these 

 in each interseptal loculse (fig. \d). 



The corallites are very tall — those figured in this work, although broken at the end, 

 were from six to seven inches high, and in general about five or six lines in diameter. 



^ Lithodendron stibdiehotomum. Minister, Beitr. zur Petref., 4th part, tab. ii, fig. 3. Rhabdophyllia ? 

 subdichotoma, Milne Edwards and J. Haime, Polyp. Palseoz., &c., p. 83. 



* D'Orbigny, Prod., v. ii, p. 32. 



^ Calamophyllia Bernardino, D'Orbigny, loc. cit., vol. ii, p. 32. 



* Miclielin, Icon., tab. xxi, fig. 3. 



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