NO. 10 DAWSON : MARINE ALGAE, GULF OF CALIFORNIA 309 



In the report of Setchell and Gardner on the Algae of the Revillagi- 

 gedo Island Expedition a specimen from Guadalupe Island, off the coast 

 of Lower California, is referred to Hooperia Baileyana J. Ag. Specimens 

 in six collections from the Gulf of California seem identical with the 

 Guadalupe Island specimen, and the cross sections of the 3-layered cortex 

 bear this out. The Atlantic specimens of Lomentaria Baileyana have a 

 characteristically unilateral branching habit. These branches are usually 

 curved so as to give a slightly curly appearance to the plants, a character 

 not at all conspicuous in the Gulf material. 



The species Lomentaria hakodatensis occurs on the coasts of China 

 and Japan. The cross sections of this species show a somewhat variable 

 size in the three layers of cortical cells, though often, if not usually, the 

 arrangement is quite the same as in L. Baileyana. The same close rela- 

 tionship is shown with the Gulf specimens, but because of the nonsecund 

 branching habit and the more erect rather than curled nature of the 

 branches there is virtually no means of distinguishing our plants from 

 the western Pacific L. hakodatensis. Thus, lacking any real criterion for 

 separating them, it seems best at present to refer all of them to that spe- 

 cies. 



D. 174, 232, 238, 261, dredged in 8-22 meters, Puerto Refugio, Jan.; 

 D. 475f, dredged in 30-36 meters, Ensenada de San Francisco, near 

 Guaymas, Feb. 



Lomentaria Drotietii sp. nov. 

 Plate 46, Figs. 1, 2; Plate 74, Fig. 2 



Frondes usque ad 8 cm. altae, basi solidae, erecta et iterum ad iterum copiose 

 ramosae usque ad systema complicatum segmentorum, gracilium, cylindratorum, 

 cavorum, nonseptatorum, superne circa 400 \i diam. et apicibus acutis, efficientes; 

 segmentis ultimis superne stratum corticale cellularum 3 x 12 m., ordine palorum 

 intus 3-4 strata cellularum plus minusve isodiametricarum 5-15 \i, et zonam filorum 

 laxorum plerumque longitudinalium cavitatem vestientium ostendentibus. 



Plants to 8 cm. high, arising from a small holdfast; fronds solid at 

 base, branching erectly, increasingly, and abundantly to a complex system 

 of slender, cylindrical, hollow, nonseptate segments, these ultimately 

 about 400 ju, in diam. and terminating in moderately acute apices ; ultimate 

 segments composed of an outer cortical layer of palisade cells, measuring 

 about 3 by 12 /x, below which are 3-4 layers of more or less isodiametrical 

 cells measuring from 5-15 /x,, these proceeding to a zone of loose, mostly 

 longitudinal filaments which line the cavity; cortical cells in surface view 

 rectangular and strongly flattened in the longitudinal plane of the seg- 



