EVANS: REPORT ON THE HEPATICAE OF ALASKA 607 
_ (3, vol. 4, p. 220, 1910). He states that the material of R. arctica 
is not juvenile, that it shows well-developed and richly branched 
plants, that the stem- and branch-leaves are well preserved, that 
the leaves and the cell structure are very different from those of 
R. Bolanderi, and that it would be quite out of the question to 
consider the two species identical. A comparison of Stephani’s 
figure of R. arctica with Pearson’s figure of R. Bolanderi (12, pl. 4, 
as R. spicata) shows that Howe’s suggestion is certainly well 
supported, and a study of Stephani’s latest description of R. arc- 
tica does not bring out any differences which are at all convincing. 
At the same time the question cannot be regarded as definitely 
settled until the type specimen of R. arctica has been re-examined. 
64. Radula polyclada sp. nov. 
On rocks. Aats Bay (goo mostly). The accompanying species 
are Metzgeria conjugata and Frullania nisquallensis. ° 
Yellowish green, becoming brownish with age, not glossy, 
growing in loose tufts: stems mostly 2-3 cm. in length and 0.2 mm. 
in diameter, copiously and regularly pinnate, a branch usually 
arising behind each stem leaf, the branches widely spreading, 
0.12 mm. in diameter, with smaller leaves than the stem, usually 
limited in growth after reaching a length of 0.5 cm. or less, often 
simple but sometimes bearing a few scattered and very short 
branches, 0.5 mm. long and 0.06 mm. in diameter, with still 
smaller leaves; rhizoids none: stem leaves contiguous to loosely 
imbricated, the lobe convex and sometimes revolute at the apex, 
spreading at an angle of about 80 degrees, slightly falcate, broadly 
ovate, about 1 mm. long and 0.85 mm. wide, attached by an 
almost longitudinal line, antical margin slightly or not at all 
dilated at the base, straight or somewhat rounded and arching 
partially across the axis, very rarely slightly beyond it, strongly 
outwardly curved to the broad and rounded apex, postical margin 
somewhat outwardly curved, forming a slight indentation at 
junction, with the slightly arched and scarcely decurrent keel; 
lobule subrhombiform in outline, about 0.55 mm. long and 0.4 
mm. wide, more or less inflated along keel and in basal portion, 
otherwise appressed to the lobe, inner margin attached for almost 
its entire length by a nearly longitudinal line, not dilated, free 
margin parallel with keel and forming an angle of about 80 degrees 
With the inner margin, outer margin subparallel with the inner 
Margin, apex rounded; leaf-cells plane, averaging 11 » along the 
antical margin, 16 » in the middle, and 22 u at the base, the walls 
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