136 BTHOP8I8 OF BKITlsir BBAWBED8. 



mous, frequently with lateral forked branc 

 the apices more or lees involute ; articulal ions pellucid, i 

 of the middle of the Btem three or four times Longer than 

 broad, the upper gradually shorter, the uppermost extremely 

 -hurt ; dissepiments coloured, armed with numerous, slen- 

 der, irregularly inserted, subulate, colourless, one-jointed 

 prickles ; tetraspores mostly solitary in each joint, erumpent 

 along the outer margin of the filament : fayellse mostly bi- 

 lobed, lateral, subtended by numerous, Btrongly incurved 

 ramuli, /. Ag. Advers. p. 27. (Atlas, PL LII. Fig. 239.) 

 Hah. On rocks and -ton"-, between tide-marks; and i 



pools parasitic on various Alga?. Annual. Summer and 

 autumn. 

 Mrs. Griffiths has for many years regarded the plant 

 here figured, as being distinct from C. ciliatum, from 

 which the nature and disposition of the prickles that clothe 

 the joints in greater or less number at once distinguish it. 

 ( '. ciliatum there is a regular whorl of stout three- 

 jointed prickles, all pointing upwards, round the centre of 

 every joint ; here we have several slender, one-jointed, 

 needle-shaped prickles scattered irregularly, and pointing 

 in various directions like the spines of a sea-urchin. In 

 young specimens the joints, at least the upper ones, are 

 tilled with a purplish fluid which makes the frond, while 

 living, appear to be fully coloured, not diaphanous ; when 

 dried this fluid is dispersed and the true nature of the 

 joint is obvious. 



237. acanthonotum (The one-spined Ceramium) ; frond slender, 

 of nearly equal diameter throughout, rigid, repeatedly dicho- 

 tomous, fastigiate, the apices strongly involute ; articulations 

 pellucid, those of the middle of the stem several times longer 

 than broad, the upper gradually shorter ; dissepiments co- 

 loured, armed on the outer edge with a single, robust, broadly 

 subulate, coloured, three-jointed prickle; tetraspores erum- 

 pent, whorled round the joint ; favella? roundish, subtended 

 by a solitary, incurved ramulus, Carm. Air/. Appin. (Atlas, 

 PL LII. Fig. 240.) 



Ceramium ciliatum, var., Haw. Acanthoceras Shuttleworthi- 

 anum, Ktz. 



II ib. On exposed rocks, near low-water mark, and on the smaller 

 Algae. Annual. Summer and autumn. ^Xot uncommon. 

 Ceramium acanthonotum is much darker in colour than 



C. ciliatum, often an intense purple; and the tufts are 



v. \ially shorter, and more densely compacted. These cha- 



