150 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



filaments unbranched or with a few unicellular branches, 9-12/i broad ; cells 

 at base once to twice as long as the diameter, above three times as long ; 

 chromatophores oval, numerous ; plurilocular sporangia linear or linear-lan- 

 ceolate, 75-ioo,u X 18-25/.1, borne laterally at or near the base of the erect 

 filaments or occasionally arising directly from the creeping filaments, sessile, 

 or the lower on short stalks; zoosporal cells 5-8/i broad, one to few seriate ; 

 unilocular sporangia sessile, ovate or elliptical, 30-40// x 1 2-18/1, borne on 

 the same tufts with the plurilocular sporangia. 



Forming minute, dark brown tufts i mm. high in the cryp- 

 tostomata and conceptacles of Fiiais evanescens. Pacific 

 Grove, California. 



9. Ectocarpus chitonicolus, sp. nov. 



Plate XV, Figs. 1-4. 



Plant 1-2 mm. high; creeping filaments numerous, branched, 15/x broad; 

 cells once to twice as long as the diameter; erect filaments mostly unbranched, 

 14/jt broad at base, somewhat narrowed above ; cells below Y^-i times as long 

 as the diameter, above 2-3 times as long, not at all constricted at the joints ; 

 chromatophores numerous, small and oval ; plurilocular sporangia lanceolate 

 or narrowly ovate, obtuse at the apex. 90-175// x 20-35//, borne laterally in 

 the erect filaments or occasionally on the creeping ones ; the lower sporangia 

 on a long or short stalk, the upper sessile. 



Forms minute tufts on the back of a chiton. Pacific 

 Grove, California. 



A variable species which approaches E. cylindricus in 

 some of its forms but is separated from it by the more 

 pointed, plurilocular sporangia and the uniformly smaller 

 size of the vegetative parts. 



10. Ectocarpus cylindricus, sp. nov. 



Plate XVI. 



Creeping filaments irregularly branched, 12-20// broad ; cells 2-3 times as 

 long as the diameter; erect filaments simple or giving off a few short 

 branches below, of the same size throughout, iS-30/ji broad ; cells below and 

 above 2-3 times as long as the diameter, in the central part as long as the 

 diameter, not at all constricted ; chromatophores numerous, disk shaped ; 

 plurilocular sporangia lateral, on a one- to several-celled stalk, erect, cylindri- 

 cal or obovate, very obtuse above, 80-200// x 35-45/^1, opposite, most abundant 

 below ; unilocular sporangia on separate filaments, ovate or elliptical, 60-120/1 

 X 30-40//, usually on a one-celled stalk, or the upper occasionally sessile, often 

 opposite. 



The plant forms a compact, velvety mass 2-4 mm. high, 

 of indefinite extent on the stems and rhizoids of Egregia 



