285 
Fresliivater Algse of North Wales. By Wni. West. 
C. Venus Ktz. D., P., Do., A., C. 
G. cynthia Not. P. 
Lat. 1 3 /X. 
C. Arclierianum Cleve. C., P. 
Specimens of this were observed from Llyn Padarn up to 25 /x in 
diameter. 
C. costatum Corda. D., Do., P. 
C. decorum Breb. C. 
C. striolatum Ehrb. D., P., Do., A., B. 
forma recta, fig. 23. 
Non curvata, rectissima. 
Lat. 33 jx. 
This differs from the type in having no curvature; several 
examples were seen, and were turned over and over. P. 
G. intermedium Ealfs. P., Do. 
G. angustatum Ktz. D., F. 
G. juncidum Ealfs. P., Do., D. 
G. lineatum Ehrb. D., S. 
G. rostratum Ehrb. Do., P., A. 
G. setaceum Ehrb. P., Do. 
G. Kiltzingii Breb. A., P. 
G. Gornu Ehrb. Do. 
*forma major Wille. G. 
G. aeutum Breb. Do., S. D. 
G. suhulatum (Ktz.). C. 
Genus Pe^iium Breb. 
P. marqaritaceum Breb. P., B., Do., A., Llyn Idwal. 
Lat. 11-25 /X. 
var. punctatum Ealfs. P. 
P. cylindrus Breb. P., Do., F. B. 
P. spirostriolatum Bark. C., P., F. Fig. 24. 
As this species appears to vary in different localities, some figures 
are given. 
I also give the dimensions of some of the figures that were drawn. 
I have noticed this variability from Maine, N. Ireland, Scandale 
in the Lake District, and Glen Shee and Craig an Lochan in 
Scotland. The parallel striae can often be seen on both the upper 
and under surfaces of the empty cylindrical frond, and then they appear 
as if they crossed each other. 
22*5 X 188 fjb from Festiniog. 
23 ’5 X 182 /X from Llyn Padarn. 
19 X 202 /X from Capel Curig. 
20 X 227 /X from ., „ 
22 ’5 X 130 /X from Festiniog. 
25 ’5 X 128 /X from Capel Curig, 
