148 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 12 



Scinaia latifrons Howe 



Plants to 14 cm tall, reddish purple, the color slightly transversely 

 banded and darker at the margins, 7-8 times dichotomously branched, the 

 branches flat with abruptly thickened margins, to 5-7 mm wide below and 

 7-10 mm above (measured above the forks), the tips rounded to slightly 

 tapered with a rounded apex; thickness to 250 /* in the central portion, 

 1,3-1.7 mm at the margins, the axial strand not distinguishable; colorless 

 epidermal cells in surface view polygonal with moderately firm walls, 18- 

 28 )u, diam., averaging about 17 /a, in transverse section appearing rectangu- 

 lar with flat outer faces, 18-21 fi tall;^*' small colored cells scattered 

 between the colorless ones; hypodermis of large spherical cells nearly in 

 one layer, 14-18 /x diam.; cystocarps chiefly marginal, rounded, 280-350 

 {i diam., the pericarp pseudoparenchymatous. 



Howe 1911, p. 500, fig. 1, pi. 28; Setchell 1914b, p. 102, pi. 11, fig. 

 23. 



These Mexican specimens are more slender than those described by 

 Setchell (1914b, p. 102), but seem substantially similar. They resemble 

 with this exception the illustrations in Howe's original paper (1911), 

 including the somewhat transversely banded appearance of the upper 

 thallus. The Ecuadorean plants seem somewhat more slender than those 

 from Mexico, and they do not appear banded. Microscopically they show 

 slightly larger somewhat turgid epidermal cells: 14-31 fx in surface diam., 

 and to 28-38 fi in radial height when sectioned. The plants also are taller, 

 reaching at least 22 cm, and with to 10-13 successive forkings. It does not 

 seem advisable at present to give them separate varietal designation, 

 though at first glance they certainly look like different things. 



Mexico: Nayarit, dredged from a depth of 21.5 meters at sta. 970 

 from a bottom of coralline and other algae near I. Maria Magdalena, 

 Las Tres Marias, no. 39-645, 9 May 1939. Ecuador: Archipielago de 

 Colon, dredged from 22 meters' depth, Tagus Cove, I. Isabela, Schmitt 

 no. 327A-34, 10 Dec. 1934. Ibid., dredged from 27-55 meters, no. 34- 

 141 (cystocarpic fragments), 13 Jan. 1934. Ibid., dredged from 9 meters' 

 depth at sta. 173, I. Baltra, no. 34-334, 22 Jan. 1934. Ibid., dredged 

 from 36 meters' depth opposite Gordon Rocks, I. Sta. Cruz, Schmitt no. 

 316E-34, 8 Dec. 1934. Ibid., dredged several large clumps from 29 

 meters' depth off Post OflSce Bay, I. Santa Maria, no. 34-289 (cysto- 

 carpic), 19 Jan. 1934. Ibid., dredged from 20 meters' depth in Gardner 

 Bay, I. Espanola, Schmitt no. 356C-34, 17 Dec. 1934. 



86 Mexican material. 



