500 HOWE: PHYCOLOGICAL STUDIES 
both unmixed with vegetative cells; carpospores 8; spermatia 64; 
thallus disintegrating and deliquescing when dried specimens are 
soaked out with fresh water. 
Scinaia latifrons sp. nov. 
Thallus gelatinous-membranaceous, thin, complanate, 10-16 
cm. long, 4-7 times dichotomous, not constricted, the segments 
5-12 mm. broad (when dry), axils rather acute and branches some- 
what patent, costa obsolete, apices obtuse or shortly and bluntly 
apiculate: cystocarps 0.17-0.32 mm. in diameter, marginal, mostly 
confined to areas I-2 mm. broad measured from the margin; 
carpospores irregularly ovoid or oblong, 10-22 long. [PLATE 28 
and TEXT FIGURE I.] 
La Paz, Vives 6, 11a (type), and 20. 
The material submitted consists of eight specimens, all of which 
are amply distinct from S. furcellata undulata, with which it grows 
associated, differing in the much broader thinner flattened mem- 
branous thallus and the marginal cystocarps. Though having a 
pronounced ‘‘Halymenioid” habit, the plants have the peculiar 
and characteristic vegetative structure and cystocarps of Scinaia. 
If aberrant in any particular it is in the absence of any costa or 
well-defined axile strand that can be clearly recognized even in a 
cross section, contrasting in this respect with S. furcellata undulata, 
with which it is associated and in which a compact axile strand is 
very manifest in cross section at least. The thallus of S. latifrons, 
even when sections of the dried material have been treated with 
potassium hydrate, shows a thickness of only 80-135u, but it is 
probable that fresh or liquid-preserved specimens would have a 
greater thickness. The thallus appears to be the thickest towards 
the margins, whether the margins bear cystocarps or not. A cross 
section of the stipe shows a compact medullary mass of filaments 
with a special axile strand only slightly indicated. The hyaline 
peripheral cells of the thallus have a height of 27-36u, averaging 
considerably higher than in the associated S. furcellata undulata. 
The color of dried specimens of Scinaia latifrons is a light brownish 
rose, while that of S. furcellata undulata is a dingy or purplish 
brown. 
Among the described species, varieties, and forms of Scinaia, 
S. latifrons is apparently most nearly allied to SS. furcellata forma 
