NO. 10 DAWSON : MARINE ALGAE, GULF OF CALIFORNIA 265 



species, as Setchell and Gardner have pointed out, is sufficiently distinct 

 to be rather readily recognized. The Gulf plants are about intermediate 

 in size between IVurdemannia miniata and Gelidiopsis variabilis, and 

 may be identified further by their loosely caespitose habit. 



This is apparently another warm-water species. Most of our material 

 is from the southern extremity of the Gulf and southward. 



M. 104 (Univ. of Calif.; isotype, AHF no. 21), cast ashore, Santa 

 Rosalia; H. 514, Sulphur Bay, Clarion Island; H. 605, dredged in 40 

 m. off San Jose del Cabo, Aug.; D. & R. 3134c, on rocks along shore, 

 Guaymas, Dec; D. 543, 533b, in rock pockets, Agua Verde Bay, Feb.; 

 D. 475b, dredged in 30-36 m., Ensenada de San Francisco, near Guay- 

 mas, Feb. 



Gelidiopsis variabilis (Grev.) Schmitz 

 Plate 70, Fig. 1 (left) 

 Schmitz, 1895, p. 148; De Toni, 1900, 410. Gelidium variabile Kiitzing, 

 Tab. Phyc. XIX, tab. 23. 



A very fine collection of plants which correspond in all determinable 

 characters with this species was made from rocks below tide level, Punta 

 San Pedro, Guaymas, D. & R. 3395, December. The plants are 8-10 cm. 

 high, abundantly branched, the whole mass forming a rounded, caespitose 

 clump of erect and divaricate branches. The blunt apices without an 

 apical cell and the elongated medullary cells remind one of the genus 

 fVurdemannia, but these examples are much larger and of a looser habit 

 throughout. Gelidiopsis variabilis is a semitropical species known from 

 East Africa, the Indian ocean, the East Indies, and from northern For- 

 mosa. The latter locality is at the same latitude as the station in the 

 Gulf of California. 



Though a consideration of the very wide discontinuity in distribution 

 would seem to discount from the likelihood of our plants being identical 

 with G. variabilis, the similarities are such that in the absence of fertile 

 material it is best to place them here awaiting further investigation. 



Family Squamariaceae 



Genus HILDENBRANDTIA Nardo 



Hildenbrandtia rosea Kiitzing 



Kiitzing, 1843, p. 384; Setch. & Gard., 1924, p. 787. 



Excellent tetrasporic material of this species has been detected on 

 rocks with corallines taken from the reef at Turner's Island, D. 757b, 

 July. The closely attached crusts are dark brown in color, irregularly 

 lobed, and spreading to about 2 cm. 



