48 
MICRASTERIAS, Ag. 
Frond mostly lenticular, as long as or slightly longer than broad, 
deeply constricted into two-lobed segments ; segments usually semi- 
orbicular, five or sometimes three-lobed ; lobes incised or divided, mostly 
ent 
spined, or rarely only sinuate at the outer margin ; central constriction 
usually linear.—Cooke’s Bnitish Desmids. , 
M. denticulata, Br¢b. Cooke’s British Desmids. Frond orbicular, 
smooth ; segments, five-lobed ; basal and middle lobes twice dichoto- — 
mous, ultimate subdivision truncato-emarginate with rounded angles; 
anched and recurved. 
Size: Length, 250 »; zygospore, 80 p (K.)-; length, 218 p; diam. 
time of separation, acquires the characteristic notched outline ae 
type, and is only distinguishable from the older half by 1s 8™ if 
size. 
Fig. 43 bis.: a, living frond; b, empty frond 5. “780PO® 
Cooke, Le. in 
Hab.: Still water, Victoria Park, W. J. Byram. Also widely distributed 
England, Wales, Scotland, France, Germany, Sweden, Norway, Denmark, te 
the United States of America. é 
Frond longer than broad, com ressed ; deeply constricted int? 
two-lobed or sinuated segments ; fegien usually pyramidal, phe | 
i iously disposed CHE 
rarely radiant, rounded or sinuated at extremities ; end lo jo tral 
incised or emarginate at the centre, rare concave ; oP 
constriction linear.—Cooke’s British Desmids, 63. 
= - um, renee Cooke’s British Desmids, 70. } 
arge, rather more than twice as long as broad, segme P 
broadest at the base and n - upwa ot lobed, the sides 
1 > i 
almost straight; ends truncate, central notch linear. EP length, 
without inflations. Size: Length, 118 »; diam., 55 » (R.) 5 K — 
96-100 yp; diam., 47-50 p (L.); length, 92-117 »; diam., 45-62 #O"" 
Cooke, Le. ‘eke 
Note of Prof. Moebius :—‘ In numerous examples of varyias he 
length, 96-150»; breadth, 42-64 »; isthmus, 11-18 p boat pilst 
length thus amounts to a little more than double the breadth, Wy 
in those found by Nordstedt in Australia and New Zealand—v# ee 
a 
