Howe: Phvcological studies 571 



mously from the more peripheral members of the medullary strand 

 and becoming afterwards apparently lateral. These branches then 

 undergo repeated divaricate forkings with a gradual diminution of 

 diameter until finally they may have only one-fifth or even one- 

 twelfth the diameter of the filaments of the central strand. 



B. NEW RHODOPHYCEAE 

 Sarcomenia filamentosa sp. nov. 



Rose-red on drying or sometimes brownish-red, very delicate, 

 gelatinous, gregarious or caespitose-pulvinate on other algae, 4- 

 16 cm. long, pseudodichotomous below; main axes distinctly cor- 

 ticated for one-half to four-fifths the length of the plant, subcylin- 

 drical or complanate, ancipitous, 0.25-0.9 mm. in diameter near 

 base, bearing occasional divaricate, rather rigid, simple or dichot- 

 omous septate rhizoids on the opposite lateral margins : cells of 

 cortex polymorphous, ranging from orbicular and triangular-ovate 

 to oblong and linear, toward base sometimes 12-16 times as long 

 as broad : main branches dissolving above in numerous narrowly 

 linear or ribbon-shaped articulate uncorticated branchlets 50—170// 

 wide, these springing from the mid-ventral * line of the next older 

 branch, their segments 7^ — 1^ times as long as broad, consisting 

 of four pericentral siphons and a pair of short cortical (?) siphons 

 arranged end to end on each lateral margin, occasional marginal 

 cells enlarged and more or less protuberant (potentially rhizoids) ; 

 cross-sections of branchlets about twice as broad as high, showing 

 a distinct costa, this especially prominent ventrally ; branchlets 

 furnished toward their apices with a secund mid-ventral row of 

 unbranched monosiphonous filaments, these 0.2—1 mm. long, 

 originating singly from a cell cut off from the anterior end of the 

 ventral siphon of each segment, deciduous in older parts, cells of 

 filament 7-20 in number, mostly 2—6 times as long as broad : re- 

 productive organs unknown. [Plate 27 ; plate 29, figures 

 I-ii]. 



On Sargassitm, corallines, etc., washed ashore. Florida : no. 

 284.4., type (Cape Florida, Biscayne Key, 29 March 1904, 

 M.A.H. — also nos. 2860 and 286 j) ; no. 2822 (Virginia Key, 

 22 March 1904). 



* We use " dorsal " and " ventral " in the sense in which these terms are employed 

 by J. Agardh (Anal. Alg. Cont. 5 : 122-149. 1899) in apparent conformity with 

 the customary usage as applied to leaves of cormophytes, the "ventral" being the 

 "inner" or "upper" side. However, a comparison with creeping species of the 

 superficially somewhat similar genus Herposiphonia suggests the possibility that these 

 terms, if used at all, should be applied in the reverse sense. 



