428 POLYPI. VAGINATI. 



gibbous ; crust cortical, containing polypi in the fresh state ; 

 thin, celliferous, and persistent when dried. 



M. ochracea, Lam. Sub-dichotomous, much branched, nearly smooth, 

 nodose at the bends j branches and ramuli erect, flexuose, free ; 

 of various colour. Ellis, Zooph. 105. 



M. relifera, Lam. (Isis aurantia, Esper.) Stem thick, branching, 

 nodose at the bends ; branches divaricate, flexuose, sub-reticula- 

 ted, thickly verrucose. Varied in colour; chiefly yellowish or pur- 

 ple. Inhabits Indian Ocean. Lam. ii. 299. 



Gen. 12. CORALLIUM, Lain. Isis, Lin. Gorgonia, Soland. 



Fixed, branched, not articulated, stiff; axis caulescent, branch- 

 ing, stony, solid, striated at the surface ; crust soft and fleshy 

 in the recent state, in which are the polypi ; thick, porous 

 and reddish when dried ; eight ciliated and radiated tentacula 

 at the mouth of the polypi. 



This genus is distinguished from Isis in not being articulated ; and the species 

 forms the coral of commerce. The axis or central portion is stony and solid, with 

 a smooth vitreous fracture, finely striated. It much resembles red wax. The coral 

 is fixed by its base to marine bodies, and always in a pendant or reversed position. 



C. rubrum, Lam. (Isis nobilis, Lin. G. pretiosa, Soland.) Bright- 

 red, rose-coloured, or whitish. Mediterranean and Indian seas, 

 and fished up as an article of commerce for the manufacture of 

 necklaces, &c. Ellis, Zooph. pi. 13, fig. 3, 4. Plate 8, Jig. 9. 



SECTION III. 



Polypiferous masses stony, with stelliform lamellae or waved la- 

 minar furrows. 



The Lamelliferous Polypi are extremely numerous in species, and much diversi- 

 fied in point of form. The polypiferous cells are sometimes in the form of lamellar 

 stars radiated from a centre, and at others in waved furrows, irregularly prolonged 

 into compartments, and furnished with lateral plates. The large masses of calcare- 

 ous matter accumulated by the polypi of this section in strata or plates rising above 

 one another and spreading around, form a great portion of the submarine rocks in 

 many seas ; and the constant increase of successive generations often raises the unit- 

 ed structure above the level of the water. Hence the origin of many islands, and 

 the often observed variation of depth in the seas of warm climates. It has been 

 conjectured that these powerful but minute agents exercise a mighty effect in the 

 formation of calcareous rocks and in changing the level of the ocean ; and that many 

 of the calcareous mountains of the present land, may have been originally the work 

 of these submarine artificers. In those which have been observed in the recent state 

 the gelatinous and animal crust on the surface seems continuous, and furnished with 

 the stellated tentacula of the polypiferous inhabitant. It is about a line in thickness 

 when the animals are expanded, but totally withdrawn into the cells at the slightest 

 touch, Lamarck divides the Lamelliferous Polypi into those which have the stellat- 

 ed mouths terminal, and those which have them lateral or spread over the surface. 



1. Stars lateral, or spread over the surface. 

 Gen. 13. OCULINA, Lam. Madrepora, Lin. 

 Polypiferous mass stony, generally fixed, branching ; the bran- 

 ches smooth, thick and very short ; some of the stelliform 

 mouths terminal, the others lateral and superficial. 

 O. virginea, Lin. Much branched, subdichotomous, milk-white ; 



