312 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL.3 



Genus GASTROCLONIUM Kutzing 



Gastroclonium clavatum (Roth) Ardiss. 



Plate 46, Figs. 6-8 ; Plate 73, Fig. 2 



Ardlssone, 1883, p. 322; Eliding, 1928, p. 38, fig. 29. 



Five collections are on hand of a Gastroclonium species which in 

 many respects shows close similarity, if not identity, with the Mediter- 

 ranean G. clavatum. 



D. 68, shallow water, Guaymas, Jan. ; D. 343, in 22 meters, Punta 

 Pefiasco, Feb. ; D. 404, on shore, Pond Island, Feb. ; D. 440, on shore, 

 San Esteban Island, Feb.; H. 673, San Bartolome Bay, outer coast of 

 Lower California, Aug. 



Varying degrees of vegetative development are shown among these 

 plants, which range in size from about 2 cm. to over 10 cm. They possess 

 the solid basal axis characteristic of the genus, though in the largest speci- 

 mens this is no more extensive than in some of the smallest. Indeed, the 

 large plants seem at first to be entirely hollow. In habit the smaller speci- 

 mens resemble very closely most of the examples present in the University 

 of California Herbarium of G. clavatum from the Mediterranean. The 

 large specimens from Guaymas are more like the illustration of one of 

 Agardh's specimens of G. clavatum as given by Eliding (1928). 



In cross section the Mediterranean specimens usually show a 2-lay- 

 ered wall, while the Gulf specimens tend more toward a 3- or 4-layered 

 wall. The latter, as well, usually have a more or less pronounced short- 

 palisade effect in the outer layer. None of these differences is convincingly 

 distinct or constant, however, and in view of the very close similarity in 

 gross morphology and the lack of any specific points of distinction, it 

 seems best to refer all of these specimens to G. clavatum while awaiting 

 further information on the range and variation of these Pacific forms. 



Family Geramiaceae 



Genus GALLITHAMNION Lyngbye 



Callithamnion endovaginum S. & G. 



Setch. & Gard., 1924, p. 771, pi. 28, fig. 62. 



J. 53b, parasitic on fronds of Grateloupia, San Esteban Island, April; 

 D. 488a, Catalina Eay, near Guaymas, Feb. 



Callithamnion veleroae sp. nov. 

 Plate 50, Figs. 3-5 



Frondes caespitosae, epiphyticae, usque ad 2.5 cm. altae, distiche ramosae; axi 

 centrali non corticata et ramis primariis ostendentes; axi centrali circa 150 M. diam., 

 in 4-ordinibus ramosa, ramis gradatim superne attenuatis, apicibus paululum ob- 



