NO. 10 DAWSON : MARINE ALGAE, GULF OF CALIFORNIA 299 



Gracilaria sp. 

 Plate 44, Fig. 1 



Fronds up to 9 cm., complanate, thick, coriaceous, from a short, terete 

 stipe, 2-3 mm. diam., expanding cuneately into the base of the blades, ir- 

 regularly, divaricately forked and lobed, the segments short, 6-8 mm. 

 (to 15) broad, with smooth margins; fronds 300-700 fx thick, with 2-3 

 layered cortex of quadrate cells about 12 ju, diam. ; reproduction unknown. 



The several examples of this plant in our collections seem surely to be 

 of this genus but are sterile. The terete basal stipe is distinctive as are the 

 littoral habit and the thick, coriaceous fronds. It appears to be related to 

 the G. Vivesii-G. Johnstonii group in the Gulf, and, since it is present in 

 so many collections, it seems well to record it in this way. 



D. 118, lower littoral rocks, Turner's Island, Jan.; D. 200, Puerto 

 Refugio, Jan, ; D. 446, San Esteban Island, Feb. 



Family Dicranemaceae 



Genus DICRANEMA Sonder 



Dicranema rosaliae S. & G. 



Setch. & Gard., 1924, p. 745, pi. 22, fig. 6. 



Recent collections have yielded a number of specimens of this little- 

 known plant. Its small size (2-4 cm.) and slender diameter of the terete 

 fronds (250-350 /x), together with the presence of a medullary core of 

 compact, thick-walled, elongated cells, distinguish it from all other Gulf 

 plants. Fertile material has, however, not yet been detected. 



M. 103, cast ashore, Santa Rosalia; D. & R. 3426, drifting along 

 southeast shore of bay, Empalme, Dec; D. & R. 3309, drifting along 

 shore east of Guaymas, Dec. ; D. & R. 3362, on shore rocks, Guaymas, 

 Dec; D. 255a, dredged in 12-22 meters, Mejia channel, Puerto Refugio, 

 Jan.; D. 614e, in oyster culture ponds, San Gabriel Bay, Feb. (slender, 

 125-250 fi diam) ; D. 546, on lower littoral rocks, Agua Verde Bay, Feb. 



Family Pliyllophoraceae 



Genus GYMNOGONGRUS Martius 

 Gymnogongrus carnosus S. & G. 



Setch. & Gard., 1924, p. 745, pi. 47a, pi. 22, fig. 1. 



J. 102, cast ashore, San Pedro Martir Island, April. Not again col- 

 lected. 



"The combination of characters of this species is not such as to make 

 it unmistakably a member of the genus Gymnogongrus. It has a Gigarti- 



