CEEAMIACEAE. 531 



Ceramium tenuissimum J. Ag. is a name that may be employed, tem- 

 porarily at least, in accordance with current usage, for a variable, perhaps 

 aggregate species that occurs in Bermuda. However, the proper application 

 of the name (first used by Roth, as a varietal name) is in doubt, and, moreover, 

 the Bermuda plants do not agree quite accurately with European plants that 

 currently bear this name. As in the following species of the genus, the corti- 

 cation is confined to a band at each node, the colored corticated nodes alter- 

 cating and contrasting with the naked usually hyaline internodes, giving a 

 transversely zoned appearance to the plant when viewed under a hand-lens. 

 The filaments are very delicate, repeatedly dichotomous, fastigiate, mostly 1-2 

 inches high, -fa-j^ of a line in diameter, the apices strongly forcipate or 

 nearly straight and erect. The mostly cylindric internodes are 2-4 times as 

 long as broad, becoming shorter above; nodal bands slightly protuberant, 2-6 

 cells wide (high), their cells irregular in form, size, and direction, 8-14 cells 

 measuring the width of the filament. The Bermuda specimens examined are 

 mostly sterile, but the tetrasporangia appear to be erumpent in a single ex- 

 trorse secund series and are somewhat irregularly divided, sometimes resem- 

 bling the so-called tetrahedral or tripartite mode and sometimes approaching 

 the decussate-paired arrangement. (Phyc. Bor.-Am. 1898 and 2098.) 



Ceramium cruciatum Collins & Hervey, creeps on Galaxaura squalida on 

 the South Shore. The erect or ascending parts are only about a line high. 

 The filaments are several times dichotomous, and about ^ of a line in diameter, 

 with forcipate apices. The hyaline uncorticated internodal cells are thick- 

 walled, often bulging, scarcely longer than broad, shorter than broad in upper 

 parts; nodal bands hardly protuberant when sterile, 2-5 cells wide (high), 

 their cells irregular in form and size, their long axes mostly lengthwise of the 

 filament, 8-16 cells measuring its width. The tetrasporangia immersed, becom- 

 ing erumpent, subsecund or subverticillate, the spores in decussate pairs. 



Ceramium byssoideum Harv. (C. transversale Collins & Hervey) is an 

 exceedingly delicate flocculent plant, reaching a length of 1-2 inches. The 

 filaments are yg ^ of a line in diameter, are repeatedly subdichotomous, the 

 branches somewhat fastigiate or corymbose, and the apices straight and erect 

 or slightly forcipate. The hyaline uncorticated internodal cells are cylindric 

 below, and mostly 2-6 times as long as broad, becoming shorter above and 

 short-fusiform, ovoid, or obovoid; nodal bands protuberant, especially above, 

 bitruncate, 3-5 cells wide (high), their cells mostly with their longer axes 

 running transversely of the filament, 2-6 cells measuring its width. The 

 tetrasporangia are subsecund, protuberant, and lightly corticated in basal 

 half, the spores irregularly tetrahedral. (Phyc. Bor.-Am. 2049, as Ceramium 

 transversale Collins & Hervey.) 



Ceramium leptozonum M. A. Howe, sp. nov. Plants delicate, Indian 

 lake or deep purplish-vinaceous, cespitose, dichotomous, fastigiate, li-3 cm. 

 high ; main filaments 40-72 n in diameter, lightly corticated at nodes only, the 

 dichotomies acute, the apices slightly forcipate or suberect; internodal cells 

 cylindric below and l?-4 times as long as broad, becoming ovoid and shorter 

 above, all provided with conspicuous fibrillar chromatophores, becoming decol- 



