Yendo: CORALLINZ VER. Th 
6a) so that we could not suppose it to belong to this species, 
had it not been provided with some normal branches in a portion 
of the frond (Pl. LII., Fig. 4). 
Although I distinguish these four forme, intermediate forms 
between them are naturally met with. Especially f. zxtermedia 
and f. polymorpha are likely to be confounded with the abnormal 
forms of Chezl. planiusculum. In this case the external thick 
margin of the apical articuli and the robust stipes are the impor- 
tant characters of this species to separate it from the latter. The 
apical articuli of Chezl. planiusculum are mostly thin and com- 
pressed, and the stipes are delicate filiform. Nevertheless, it 
would not be an unreasonable supposition that the hybrid between 
Chel. frondescens and Cheil. planiusculum may occur in nature. 
Common: between tide marks, also in pools. 
5. Cheilosporum planiusculum (Kiitz.). Pl. LIII., Figs. 1-3; 
Ele VIL, Figs. 9 and ro. 
Fronde dense czspitosa suberecta, 3-7 cm. alta, superne com- 
planata, bi-tripinnata; articulis axium inferioribus tenuioribus 
cylindraceis mediis superioribusque compressis late triangulari- 
bus subcostatis, pinnarum sagittatis lobis acutis spe cordatis, 
pinnularum ancipitibus lanceolatis vel linearibus, ultimis obo- 
vatis compressis; geniculus brevissimis; conceptaculis hemi- 
spheericalibus, 2—5 in articulo instructio. 
Corallina planiuscula Kiitz., Tab. Phyc., VIII., p. 31, taf. 
Ba, fis: 3. 
The present plant is extremely variable in the shape of its 
articuli, and sharp definition is hard to give. Kiitzing counted 
four forme in the original description (7. c.) though I could not 
find any form referable to /. /ac¢nzata. The other three forme 
may be found mixed together in one bunch of the plant, often 
branches of different forms occurring in one individual. In an 
extreme instance, especially in a plant growing at high-tide 
mark, the frond becomes a moniliform filament with a few 
articuli of the normal shape (Plate LII., Fig. 3). Generally 
speaking, the articuli of the upper and middle portions are 
sagittate, with lobes thin, delicate and sharp at the upper angles, 
and with evident ribs at the middle; the pinnules are thin, 
spatulate or lanceolate. As the consequence, an articulus is 
not approximate with its adjacent ones as in Chedl. frondescens 
f£. ¢ypeca (comp. Pl. LVI., Fig. 4, and Pl. LVI., Fig. 10). 
