500 University of California Publications mi Botany [yoh. 8 



with chromatophores above, hyaline below; cryptostomata with fas- 

 cicles of included hairs scattered promiscuously over the upper sur- 

 face; reproduction by zoosporangia, arising from the same basal cell 

 as the multicellular paraphyses; gametangia unknown. 



Setchell and Gardner, in Setchell, Alg. Novae I, 1912, p. 233, pi. 25, 

 figs. 1-4. 



•^53 "■ 



Hapterophycus canaliculatus S. and G. 



Plate 41, fig. 54, and plate 77 



Fronds up to 5 cm. wide ; color yellowish brown ; sporangia 65-75/x 

 long, 18-25;u. wide ; paraphyses cylindrical, composed of 4—7 cells, 6-7ju, 

 wide, 12-1 6/x long. 



Growing on rocks in small tide pools, or on the horizontal surface 

 of flat rocks subjected to wave action, in the upper littoral belt, or 

 even above high-tide limit. San Pedro, California. 



Setchell and Gardner, in Setchell, Joe. cit. 



Hapterophycus, up to the present, is a monotypic genus, canali- 

 culatus being the only known species. It has been found only in the 

 vicinity of San Pedro, California, but doubtless may extend much 

 farther south. 



In its histological structure, it resembles Ralfsia deasta, especially 

 in the free lobes of that species. Since the publication of the original 

 description, it has been discovered that on the upper surface there 

 are numerous, small, inconspicuous cryptostomata containing fascicles 

 of hairs which do not extrude beyond the surface of the frond. 



12. Lithoderma Aresch. 



Thallus consisting of a thin parenchymatous disk, circular or irre- 

 gular in outline, of indefinite expansion, attached to the substratum 

 by the entire under surface without rhizoids ; hairs absent ; growth 

 in diameter marginal, and in thickness by horizontal cell division, the 

 cells arranged more or less regularly in vertical rows ; reproduction by 

 zoosporangia and by gametangia borne in sori on different individuals, 

 the zoosporangia on the outer ends of the vertical rows of cells, the 

 gametangia either terminal on the vertical roM^s of cells or lateral on 

 special filaments. 



Areschoug, Observ. Phyc, part 3, 1875, p. 22. 



The type selected by Areschoug to represent his newly proposed 

 genus is Lithoderma fatiscens, which is the Ralfsia extensa of Crouan 



