18 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 26 



California, Berkeley (284038). An isotype fragment is in Herb. A. 

 Hancock Foundation. 



Type locality: Growing on log floats in the harbor at Victoria, 

 Vancouver Island, Canada. 



Mexican distribution: Pacific Baja Calif. — D. 103, Cabo Col- 

 nett; D. 8789, Bahia San Quintin; D. 1577, Punta Maria; D. 9757, 

 Bahia Blanca, 18-30 m.; D. 35-40, 13426, Bahia Santa Maria, Isla 

 Magdalena. 



This Mexican material corresponds closely with Gardner's original 

 description except that in some of it a greater attenuation of the 

 branchlets is evident, due, perhaps, to the local environmental conditions. 



Antithamnion lherminieri (Cr. & Cr.) Nasr 

 PI. 5, fig. 5 

 Nasr 1941, p. 66, fig. 9-10; Dawson 1956, p. 53, fig. 51. Callithamnion 

 lherminieri Crouan & Crouan, in Maze & Schramm 1870-77, p. 144. Anti- 

 thamnion antillanum Borgesen 1915-20, p. 226, fig. 213-216. 



Thalli minute, epiphytic, consisting of a creeping axis producing 

 erect branches about 1 mm high; creeping axes 30-70 /x in diameter, of 

 cells about 4 diameters long, with sparse indeterminate branching, 

 producing from each cell an opposite pair of ascending, determinate, 

 compound branches, attached by short, pluricellular rhizoids with 

 discoid tips arising, usually singly, from the basal cells of the more 

 ventral of each opposite pair of branches; determinate branches of cells 

 10-15 [x in diameter, 1.3-3 diameters long, alternately branched from 

 nearly every cell, the tips blunt; gland cells lying next to two cells on 

 ultimate branchlets; reproduction not observed in Mexican material. 



Type: A Maze & Schramm collection no. 1259 on "Galaxaura 

 umbellata" , probably to be found in Herb. Crouan at the marine 

 botanical station, Concarneau, France. 



Type locality: Guadeloupe, West Indies. 



Mexican distribution: Pacific Baja Calif. — D. 35a-40, on a 

 decaying algal fragment, Bahia Santa Maria, Isla Magdalena, 20 m. 

 Gulf of Calif. — D. 3095, 3166, on algal fragments in drift, 5 km. N. 

 of Cabo Pulmo. 



Antithamnion mcnabbii Daws. 



PI. 5, fig. 4 

 Dawson, 1959. p. 28, fig. 7. 



Thalli minute, abundantly branched and densely aggregated, to 

 8 mm tall, forming soft, red tufts on short articulated corallines on rock 

 surfaces, consisting of interwoven, branched monosiphonous, ecorticate 

 axes about 25 ft in diameter below, bearing numerous, generally simple, 

 multicellular rhizoids, each arising from the basal cell of a determinate 

 lateral branch; axial cells about 150 ^ long below, 100 p, above and 



