504 



BULLETIN OF THE BUREAU OF FISHERIES. 



above, branches sometimes elongated and somewhat zigzag, gradually tapering, and divided into numer- 

 ous fine branchlets toward the apices, branchlets arising laterally, often forming dense fastigiate tufts, 

 especially toward tHe apices; pericentral cells six to eight, usually six, rarely five, segments i diameter 

 long or less below, 2 to 3 diameters above, no cortex; tetrasporangia in somewhat torulose series in the 

 branchlets; antheridia linear-oblong, acute at apices; cystocarps broad-ovate, toward the apices of small 

 branches; color dark brownish or blackish purple. 



Warm and temperate North Atlantic. 



Occasionally abundant on buoys, Beaufort, N. C., July to September, sometimes fruiting. One mass 

 on buoy in Sound, Port Royal, S. C., and very abundant on Gracilaria multipartita var. angustissima 

 at mouth of one creek, August, 1909. 



39 



Fig. 36. Chondria litioralis, apex of branch, X 40. 

 Fig. 37. Chondria littoralis (?), apex of branch, X 40. 

 Fig. 38. Chondria dasyphylla, apex of branch, X 40. 

 Fig. 39. Chondria dasyphylla, anthreidium. X 157. 

 Fig. 40. Chondria dasyphylla, young plants, X 157. 



Fig. 41. Polysiphonia spp., cross sections of stems. A. 

 P. harveyii. B. P. denudata. C. P. nigrescens. X 40. 



Fig. 42.Spermothamnion ini'estiens, partly divided tctra- 

 sporangium producing vegetative filament, X 263. 



Fig. 43.Griffithsia sp. X 40. 



This is the only determinable species having six pericentral cells observed in this region. The 

 habit, while more or less dense, is characteristic, and the determination is less difficult than in most 

 species of the genus. The plants growing on the buoys are small (2 to 4 cm.), while those from the creek 

 at Port Royal are 6 to 15 cm. tall. According to .Harvey, this species is very abundant in the harbor of 

 Charleston, S. C., during January and February. 



4. Polysiphonia nigrescens (Hudson) Greville. Fig. 4iC; PI. CIX, fig. 3. 



Conferva nigrescens, Hudson, 1778, p. 602. 

 Polysiphonia nigrescens, Greville, in Hooker, 1833, p. 322. 

 Polysiphonia nigrescens, Harvey, 1853, p. 49. 

 Polysiphonia nigrescens, Farlow, 1882, p. 174. 

 Polysiphonia nigrescens, De Toni, 1903, p. 940. 



Fronds forming erecf tufts 4 to 30 cm. tall, setaceous and rather rigid below, flaccid and much 

 branched above, branching pinnate, alternate, decompound, rather regular, young branches usually 



