TRIBE I. ASTR^E ACE A. 185 



14. Muss A FRAGILIS. (Dana.) 



M. glomerata, vix stipitata aut partim incrustans, convexa. CoraUum 

 fragile, infra valde et acute lamello-striatum ; supra, gyris J-" latis, 

 ad marginem dilatatis; collibus 4-5'" latis, rotundatis etpkrumque sul- 

 catis; septo $" crasso et ad apicem duabus lineis cakareis longitudi- 

 nalibus iV" sejunctis ; lamellis fragilibus, tenuiter dentatis et apice 

 denticulatis. 



Glomerate, scarcely stipitate or partly incrusting, convex. Corallum 

 fragile ; below, strongly and acutely lamello-striate ; above, gyri 

 to of an inch broad, dilating at the margin of the corallum ; ridges 

 4 to 5 lines broad, rounded and somewhat sulcate ; septum of an 

 inch thick, and at top two longitudinal calcareous lines T V of an inch 

 apart; lamellae fragile, dentate, with the teeth slender, at apex 

 denticulate. 



Plate 8, fig. 7, outline of lamellae and transverse profile of trench. 



West Indies, Bermudas. J. Redfield. 



The thin and fragile lamellae, slenderly dentate, approximate this 

 species to the Manicinse. The trenches are nearly triangular in outline. 

 The polyp-centres at the bottom of the trenches consist of aggregated 

 points, but are hardly convolute. The specimen examined was fur- 

 nished the author, for description, by Mr. J. Redfield of New York. 

 It differs decidedly from the crispa in its more convex form, thinner 

 lamellae, sulcate ridges, and more numerous and slender dentations. 



Fungus marinus, foliolis erectis, pertenuibus, non dentatis, cui nomen est Brassices 

 Pompeiance, Seba, iii. tab. 109, No. 9. Represents a worn specimen probably of this 

 species, and is a good figure of many specimens seen by the author (see plate 8, fig. 12). 

 The two thread-like lines along the septum are ^ of an inch apart as in the above, and 

 the gyri are of nearly uniform width. The coral being quite cellular, the ridges are 

 often worn off nearly smooth, in beach specimens. Lamarck refers Seba's figure to 

 his Meandrina (Mussa) gyrosa, which, as figured by Ellis, has very stout and firm 

 septa, and is a much heavier and more solid species. 



Another allied species is common in worn specimens in our collections, which has the 

 gyri 5 to 9 lines broad, and less regular than in the preceding, and the two thread-like 

 lines along the septum twice as near, with minuter cellules between them. It grows to a 

 large size, at least a foot in diameter. Beach specimens have the ridges less worn off 

 than in thcfragilis. This is probably Seba's No. 10, tab. 109. The species may also 



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