232 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 3 



in rock pools measuring 31° C, growing with Amphiroa and Jania, but 

 was not seen at all in January at the same station. 



Family Sporochnaceae 



Genus NEMAGYSTUS Derb. & Sol. 



Nemacystus Brandegeei(S. & G.) Kylin 



Kylin, 1940, p. 49. Meneghiniella Brandegeet Setch. & Gard., 1924, p. 5 ; 

 1925, p. 549, pi. 47, fig. 11, pi. 49, fig. 16. 



Kylin did not have examples of this species when he wrote his revision 

 of the Chordariales, and he was able to judge the systematic position of 

 this plant only from the published description and figures, the latter quite 

 inadequate for his purpose. A reinvestigation of the type specimen together 

 with another specimen of recent collection confirms Kylin's opinion. 

 Setchell, in a marginal note in his personal copy of the Melanophyceae 

 (S. & G., 1925), had also reached the conclusion that the species belonged 

 to the genus Nemacystus of Derbes and Solier, but this was never pub- 

 lished. 



The genus as delimited by Kylin includes those plants having a single 

 central axis-strand, growth in length by means of an apical cell rather 

 than by intercalary division, and in the presence of vegetative hair- 

 branches clothing the whole of the thallus surface. 



Recent collections of Sargassum leaves show this species is epiphytic. 

 Only a single example was found, this at the northernmost station in the 

 Gulf, whereas the type came from La Paz in the southern region. 



Brand. 24, cast up at La Paz ; D. 359, on a Sargassum leaf dredged 

 in shallow water near shore at Punta Penasco, Sonora, Feb. 



Family Scytosiphonaceae 



Genus COLPOMENIA Derb. & Sol. 



Golpomenia sinuosa (Roth) Derb. & Sol. 



Derbes & Solier, 1856, p. 11, pi. 22, figs. 18-20; Setch. & Gard., 1925, 

 p. 539, pi. 45, figs. 82-86. 



To avoid added confusion, though Sauvageau (1927, p. 350) has 

 questioned the occurrence of true Colpo7nenia sinuosa on the Pacific coast 

 of North America, the name is here used by which the plants under con- 

 sideration have long been known and may most readily be recognized. 



From the material now at hand it is clear that several forms or varie- 

 ties of this species are abundant perennial inhabitants of the shores of the 



