V. CERAMIACEiE. 235 



branched ; lower branches irregularly divided, the upper decompound-pinnate and 

 plumukte ; plumules flexuous, distantly and rather irregularly pinnate, the pinna3 

 alternate or secund, slightly tapering, obtuse, often ramulose toward the point ; 

 articulations of the branches six or eight times, of the ramuli three to six times as 

 long as broad ; tetraspores elliptical, tripartite, secund, several on each pinna ; 

 favellae binate. J. Ag. Sp. Alg:2,p. AQ. Harv. Phyc. Brit. t. 262. Phlebothamnion 

 byssoides, Kiitz. Sp. Alg.p. 657- Callith. arachnoideum^ Ag. Sp. Alg. p. 181. Var. /3 

 unilaterale ; of smaller size and still greater tenuity than the ordinary form ; the 

 branches and ramuli very frequently secund, the plumules irregular, sometimes 

 alternately pinnate, sometimes secundly pectinate. Cat. unilaterale, Harv. MSS. 

 (not of Zanard.) Yar. y fastigiatum ; branches fastigiate, the lesser ones densely 

 ramulose at the tips. Var. 8 Waltersii ; more rigid than usual, the upper branches 

 distichously decompound-pinnate, ramuli remarkably patent. 



Hab. New York Harbour, in several places from Hellgate to Port Hamilton, 

 Messrs. Hooper.! Walters., Congdon, Calverley, i^-c. Var. /3, Massachusetts Bay, 3frs. 

 Ifudge, Dr. Durkee, Miss Mitchell, Capt. Pike, eye. Greenport, Prof. Bailey, 

 W.H.H.^c. (v. v.) 



Tufts large and dense, one to three inches high. Filaments much finer than 

 human hair, excessively flaccid, soft and sub-gelatinous, collapsing into a clot when 

 removed from the water, much branched ; the lower branches very irregular, some- 

 times close together and dividing at short intervals, sometimes more distantly 

 branched ; the upper branches repeatedly decompound-pinnate. Plumules some- 

 times long and virgate, narrow, simply pinnate or having the upper pinnules 

 pinnellate or secundly ramulose ; sometimes shorter and more ovate, and frequently 

 with a flexuous rachis. Articidations destitute of veins, except near the base of the 

 stem, many times longer than broad in the larger branches, four or five times or 

 more in the smaller, cylindrical. Tetraspores on the inner face of the pinnulae, few 

 or several, secund, elliptical. Favellce not seen on American specimens. Colour, a 

 fine purplish rose-red. Substance very tender. 



Var. /3 is smaller and still more slender than the common form, with longer 

 internodes, and its typical state is readily known by the strong tendency to secund 

 ramification ; but this character is very variable. 



In some of the numerous and beautifully preserved specimens with which Mr. 

 ^ alters has favoured me, the ends of the upper branches are remarkably fastigiate 

 and densely ramulose, and the external aspect is strikingly similar to that of C. 

 corymbosum. Another specimen from the same gentlemen, dated July 6, 1851, has, 

 to the naked eye, the aspect of C. gracillimum, the upper branches being distichously 

 decompound-pinnate, with an ovate outline ; all the ramuli remarkably patent and 

 even recurved, the ultimate ones very generally secund. The substance appears 

 rather more rigid than usual ; and had I received this specimen alone it might 

 possibly have passed for a distinct species ; but after comparison with a large 

 number of North American specimens of C. byssoideum, I fear its distinctive 



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