CORALLINACE.E. 103 



ORDER IX. CORALLINACE^E. 



Corallineao, Lamour. Cor. Class, p. 244 ; Dne. Class, p. 

 63; Endl. 3d Suppl. p. 48; Harv. Ner. Austr. ined.; 

 Lindl. Veg. King. p. 25. Corallineae and Spongiteae, Kuiz. 

 Phyc. Gen. pp. 387, 385. Corallinidae and Nulliporidae, 

 Johnst. Brit. Lith. p. 205, &c. 



DIAGNOSIS. Rigid, articulated or crustaceous, mostly cal- 

 careous sea-weeds, purple when recent, fading on exposure 

 to milk-white, composed of closely packed, elongated cells 

 or filaments, in which carbonate of lime is deposited in an 

 organized form. Tetraspores tufted, contained in ovate or 

 spherical conceptacles (ceramidia) furnished with a terminal 

 pore. 



NATURAL CHARACTER. Root, where this organ is mani- 

 fested, an expanded, crustaceous disk, often spreading widely. 

 Frond almost always calcareous, effervescing strongly when 

 thrown into acids, rarely destitute of lime, very variable in 

 aspect and habit. The lowest forms of the order are simple 

 incrustations, spreading, like the crustaceous lichens, over 

 the surface of rocks or the fronds of the larger Algae. In the 

 smaller of these the crust is a mere film, as thin as paper, ge- 

 nerally circular, and extending by means of small additions 

 to the circumference ; so that the frond becomes marked, as 

 it advances, with concentric circles. In the larger, the crust 

 is thick and. stony, rising here and there into prominences, 

 and sinking in depressions. Still further advance manifests 

 itself by the crust assuming a branching habit; at first, pa- 

 pillae rise from the surface ; these thicken, and widen and 

 lengthen, and at length throw out branches, till a shrubby 

 frond, of stony hardness, but extremely brittle, is formed. 

 All these changes in character take place within the limits of 

 a single genus, Melobesia. Nearly related to this (and by 

 many botanists considered identical) is Mastophora, a genus 

 in which the frond is expanded into leafy lobes, usually fan- 

 shaped, sessile or stalked, but not adnate to rocks, of a flex- 

 ible substance, containing a smaller portion of carbonate of 

 lime than in the former group. Some of these have the habit 

 of Padina, but differs from that genus in being of a red co- 

 lour. They are the most perfectly-organized of the leafy or 

 frondose Corallines (Nulliporeee). The articulated, or true 



