146 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 12 



KEY TO SPECIES 



1. Branches flat S. latifrons 



1. Branches nearly or quite cylindrical 2 



2, Plants small, height less than 10 cm S. complanata 



2. Plants becoming much larger 3 



3. Branching erect, the intervals averaging about 2 cm or more; 

 colorless cells of the epidermis 14-24 /x diam., 18-25 /x deep . . 

 S. Johnstoniae 



3. Branching more bushy and close, at intervals of 1.5 cm or rather 

 less ; small colored cells occasional in the epidermis, the colorless 

 cells 24-28 /x diam., 35-45 /x. deep S. Setchellii 



Scinaia complanata (Collins) Cotton,/. 



Plants dull red purple throughout, soft in substance, to 5 cm (or 

 more ?) in height, closely branched 7-8 times successively, the segments 

 to 3 mm diam. in the upper part and to 2 mm in the lower portion meas- 

 ured above the forks; apices of branches rounded to obtuse conical; axis 

 fairly evident in the lower part of the dried plant, less so above; epidermis 

 of colorless cells polygonal and thin walled in surface view, ranging from 

 11-28 fi diam., averaging 17.5 fi; in radial aspect rectangular, about 21-28 

 fi tall, the outer face flat; small colored cells between the colorless ones 

 rare; hypodermal layer single, of rounded compressed cells 11-17 fi diam., 

 7-10 )U tall in section, about one to each epidermal cell ; medulla extremely 

 sparse, of very delicate filaments 2-3 fx diam., the axis (soaked up) to 

 about 150 ;u, diam., of some scores of larger filaments and a few delicate 

 ones. 



Setchell 1914b, p. 100. 



This plant differs from S. Johnstoniae in its short, densely branched 

 habit, relatively slightly taller epidermal cells, and the more extensive 

 axial strand. From the West Indian S. complanata it is perhaps separated 

 by structure again, for the epidermal cells appear to be more distinctly 

 taller than broad, the hypodermal layer of larger cells seems more regular, 

 and the axial strand is fairly extensive. 



Mexico: Nayarit, dredged from 21.5 meters' depth oflF a bottom 

 with many coralline and other algae, sta. 970 near I. Maria Magdalena, 

 Las Tres Marias, no. 39-647, 9 May 1939. Costa Rica: dredged at 

 4-7 meters' depth in Cocos Bay, Puerto Culebra, Schmitt no. lUA-SS. 

 13 Mar. 1933. Ecuador: Archipielago de Colon, dredged from 22 

 meters' depth, south side of Tagus Cove, I. Isabela, Schmitt no. 327B- 

 34, 10 Dec. 1934. 



