NO. 10 DAWSON : MARINE ALGAE, GULF OF CALIFORNIA 321 



Genus GENTROGERAS Kiitzing 

 Gentroceras clavulatum (Ag.) Mont. 



Montagne, 1846-47, p. 140; Setch. & Card., 1924, p. 779. 



This species has been found at lower littoral shore stations in all 

 parts of the Gulf and at various times of the year. It is evidently a com- 

 mon perennial there as it is in warm and temperate waters in many parts 

 of the world. 



Gentroceras bellum S. & G. 



Setch. & Gard., 1924, p. 779, pi. 26, fig. 48, pis. 40c, 78. 



M. 85, cast ashore at Guaymas, June. Not again collected. 



Family Delesseriaceae 

 Genus BRANGHIOGLOSSUM Kylin 

 Branchioglossum Woodii (J. Ag.) Kylin 



Kylin, 1924, p. 8, fig. 2a. Branchioglossum MacDougalii Gardner, 1927, 

 p. 103, pi. 20, fig. 4, pis. 33, 34. 



Comparison of Gulf specimens with examples of Branchioglossum 

 Woodii from the California coast shows hardly enough difference to dis- 

 tinguish the former as a separate species. 



MacDougal, growing on Sargassum, Puerto Libertad, Nov., 1923 ; 

 D. 378, dredged in 22 meters, Tepoca Bay, Feb. ; D. 475e, dredged in 

 30-36 meters, Ensenada de San Francisco, near Guaymas, Feb. 



Genus HYPOGLOSSUM Kiitzing 

 Hypoglossum attenuatum Gardner 



Gardner, 1927, p. 104, pi. 20, f^g. 3, pis. 35, 36. 



MacDougal, epiphytic on Sargassum, Puerto Libertad, Nov., 1923; 

 D. 267, dredged in 12-22 meters, Puerto Refugio, Jan.; D. 60, dredged 

 in 4-6 meters, Guaymas Bay, Jan.; D. 303, dredged in 60-80 meters, 

 Gonzaga Bay, Jan. 



Genus SORELLA Hollenberg 

 Sorella pinnata Hollenberg 

 Plate 47, Figs. 3, 4 

 Hollenberg, 1943, p. 578, figs. 15, 16. 



Plants 1-3 cm. high, semiprostrate in inferior parts where attached 

 to substratum; frond segments flat, lanceolate, .5-2 mm. broad, with 

 acute, obovate to lanceolate, irregularly arranged pinnae with an incon- 

 spicuous midrib and microscopic veins running into pinnae, monostro- 

 matic except at midrib and in lower parts; growth from an apical cell 



