NO. 1 DAWSON : MARINE RED ALGAE OF PACIFIC MEXICO 35 



fronds of a single plant quite uniform ; thallus structure consisting of a 

 central medullary tissue of colorless, interlacing longitudinal filaments 

 emitting radially the branched, pigmented, assimilating filaments which 

 form the loose, cortical region; plants normally monoecious, but often 

 apparently dioecious because of protandry. 



Type: Holotype not designated, but represented by a specimen 

 collected by Major Velley and sent with description to Withering, now 

 in the Free Public Museums, Liverpool, England. A syntype annotated 

 by A. D, Cotton is in the Herbarium at Kew. 



Type locality: On rocks off the "Beal," or Bill, at the extremity 

 of Isle of Portland, Dorsetshire, England. 



Mexican distribution: Pacific Baja Calif. — D. 4220, Islas Los 

 Coronados, June; D. 1447, Punta Santa Rosalia, Apr.; D. 9423, Islas 

 San Benito, May; D. 9878, South Bay, Isla Cedros, Apr.; D. 8336, 

 8564, Isla Guadalupe, Dec. ; D. 9154, Bahia Asuncion, Apr. 



The Isla Guadalupe specimens represent a slender form in which the 

 main axes seldom exceed 1 mm. in diameter, while the Islas Coronados 

 plants represent a very heavy form up to 6 mm. in diameter. 



Nemalion pulvinatum Grunow 

 Plate 15, fig. 1 



Grunow, apud Holmes, 1896, p. 259, pi. 12, fig, b; Okamura, 1907, 

 pi. 9, figs. 2-9 ; Okamura, 1936, p. 414, fig. 192. 



Thalli gregarious, saxicolous, tufted, lubricous, with many erect 

 branches coalescent at the base in the common attachment stratum, 1-2 

 cm. high, densely, irregularly, dichotomously, polystichously, divergently 

 branched at short intervals, cylindrical or compressed, 0.8-1.2 mm. in 

 diameter, reduced above to blunt apices ; structure consisting of more or 

 less longitudinally arranged medullary filaments 10-13 /* in diameter 

 giving rise to moniliform, dichotomous filaments of the peripheral layer 

 and rhizoidal cells from the lower cells of the latter running inwards and 

 downwards; cells of the moniliform peripheral filaments 10-12 [x in dia- 

 meter, the terminal one somewhat bulbous, to 16 fi in diameter; repro- 

 duction not seen. 



Type: Holotype is Tanaka 13 in the Herbarium of the Museum 

 of Natural History of Vienna, Austria. 



Type locality : Coast of Japan. 



Mexican distribution: Gulf of Calif. — D. 7128, Bahia Agua 

 Verde, Baja Calif., Mar. 



