I ,. i , Vid Medd Nai Foren. Kjul.nli.ivn 1908. p. 30), who has collected 



plants extei in the Danish West Indies from depths of to 30 meters, finds the 



the v rj 1< ■ texture ol the flabellum, and by its 



He al ribi ■ and figures the chromatophores as 



>rd with our observations, for in all the specimens o) l.nigricans 



j n Nv j lu i, w romatophores, we found them t<> be round without exception. 



pi. mts \ 11 om brown to greyish or blackish brown. The 



om pale to dark cool brown, bul sometimes is more fulvous. 



imens which we have examined the filaments are colourless, dotted with 



and only here and there stuffed with brown (rarely fulvous) contents. It 



rown st;iin of the filaments, which is preserved in the dried plants, 



from the pickled specimens by the action of the alcohol or picric-alcohol. 



igricans were discovered and described by Dr. Howi (Buil. Torr. 



ib XXXIV. 1907. pp. 504 — 507) upon a plant which he refers to his forma fulva. 



He describes them as capitate or subclavate filaments, protruding abundantly from the surface 



of the thallus, the sporangia hein- half as long as the supporting stalk. The) were intensely 



n when young, brown when older; and the) contained about 3 -5 ovoid, pyriform, 



rate-ellipsoidal, or difform bodies, which he concluded wen- probably .ipl.mosp.irrs. The 



ingiophores arise dichotomously, though sometimes appearing lateral, and are often more 



slender than the vegetative filaments from which they spring. 



We have found sporangia and old sporangiophores on plants of . /. nigricans collected 

 at ». Isl.md, Grenada, by Mr. ('.. Murray in August [886, and preserved in alcohol. 



i ie plants have large thin fronds and are borne on thick coarse well-developed rhizomes. 

 The sporan ■ all empty; they correspond nearly enough in si/c with those described by 



I )r. Howi for his forma fulva. Similar sporangia occur on a small dried specimen "ex Antillis" 

 in Herb. Shuttleworth in Herb. Mus. Brit. 



. /. nigricans can be classed with . /. Rawsoni and . /. Ma ei in the lat e of its 



filaments It differs however from . /. Rawsoni in having its filaments less thin-walled and 



tlly more deeply and moniliformly constricted, and in the possession of a more or less 



llate frond. From . /. Mazei it differs in having moniliform filaments; those of . /. Mazei 



lindric. 



A short note is necessary about a Jamaican specimen in the British Museum, namely 



Phycotheca Bor.-Amer., issued as . /. longicaulis. It is undoubtedly . /. nigricans, 



rhizomatous plant, which appears to have suffered injury twice and to have 



ns < ach time. < Ine of these proliferations is a stipitate spathulate flabellum, 



of A. nigricans. One of the other outgrowths looks like a little prolifera- 



... because it has the structure of A. Rawsoni. It must therefore be a 



vhich has developed epiphytically on the rhizome of the bigger plant. 



at Mr. Howi (in Buil. Torrey Bot. Club XXX. 1907. p. 511) says that 



in three sets and found them all, as well as n° 771, to 1"' . /. Rawsoni 



the material issued under n" 77.. is mixed with A. nigricans." 



