264 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 17 



with such a midrib indistinct or lacking; branching primarily divaricate- 

 ly dichotomous in one plane, secondarily pinnate proliferous from the 

 margins; segments often overlapping, (5) 8-15 mm. broad, entire except 

 for the developing proliferous branchlets, the margins sometimes undul- 

 ate, the apices broadly rounded, 40-70 ix thick in upper parts of sub- 

 littoral plants, to 110 ft thick in intertidal plants; lower parts secondari- 

 ly thickened by repeated periclinal divisions of the cortical cells ; struc- 

 ture consisting of a narrow medulla of branched, interwoven cellular 

 filaments about 5 ;u, in diameter and commonly with a few refractive 

 filaments running through the middle, a subcortex of 1-2 layers of 

 rotund cells 8-12 fi in diameter, and a deeply pigmented cortex of a 

 single (and sometimes partial second) layer of small cells 4-6 /x in dia- 

 meter; cystocarps scattered but numerous, embedded in the blade, 200- 

 250 IX in diameter, prominently bulging on either side of the blade, but 

 more so on the side bearing the ostiole ; carpospore mass compact, dis- 

 tinctly pedicellate on the old auxiliary cell ; antheridia and tetrasporangia 

 unknown. 



Type: Holotype is Dawson 49-40, Jan, 22, 1940, on sheet 35, in- 

 cluding vial 3 and slides 002-003, 2181-2182, in HAHF. 



Type locality: On muddy bottom at a depth of 4-6 m., outer 

 harbor, Guaymas, Sonora, Mexico. 



Mexican distribution: Gulf of Calif. — D. 765, intertidal, 

 Isla Patos, Feb. ; Drouet & Richards 3308, drift, 4 km. east of Guaymas, 

 Dec; Dawson Sta. 38, Feb. 19, 1940, dredged, 16-28 m., Puerto Escon- 

 dido; D. 6911, dredged, 8-18 m.. Canal de San Lorenzo, Isla Espiritu 

 Santo, Mar.; Howell 891a, dredged, 37 m., Bahia San Lucas, Aug. 



Gryptonemia decolorata Taylor 

 PI. 2, fig. 15 



Taylorl945,p.202, pi. 83, fig. 1. 



Thalli to about 5 cm. high, dark, dull reddish when dry, staining the 

 paper dark brown, thin, firmly membranous, irregularly branched, the 

 branches contracted at the bases, 3-12 mm. broad, 80-100 /x thick; apices 

 rounded ; margins crisped and erose, submicroscopically aculeate-den- 

 tate ; structure consisting of a narrow medulla of slender, closely placed, 

 intertwined filaments with lumena about 2-3 /x in diameter and coalesced 

 walls, a subcortex of two irregular layers of which the cells of the inner 

 are larger and about 9-12 fx in greater diameter, and a cortex of 1-2 

 layers of compactly arranged cells 4-8 fx in diameter of which the cells 

 of the outer layer are anticlinally elongated; tetrasporangia not in sori. 



