90 NOTICES OF BOOKS. 
countries together there are found 362 species.—Amongst the more _ 
noteworthy forms should be mentioned a triangular form of Cosmariun — 
Meneghinit, var. (C. crenulatum. De Not.); also Hyalotheca dissiliens, 
B. bidentula, and y. tridentula. These two last-named, as regards the — 
figure of the cells, form a transition to the genus Desmidium, especially | 
the peculiar species D. cylindricum, Of most of the Euastrum species 
a scrobiculate form was encountered. In the enumeration of the 
species the author follows the plan of Lundell’s Work, “ De Desmi- 
diaceis, que in Suecia invente sunt, observationes critice ” (in Nov. 
Act. reg. Soc. Sci, Upsal., ser. 3., vol. viii., fase. 1, 1871). He-does — 
e new forms are:—Euastrum sublobatum (Bréb.), 0. vat — 
erispulum [this appears indeed a distinct forn osmar' 
ag : S 
onomazum, — 
Lund., 8. polymazum, n,v. [distinguished from Lundell’s form by : 
possessing three (not one only) emarginate tubercles on each front of 
each i 
broad ; constriction deep, linear ; segments subtrapezoid, lower 
angles broadly-rounded, whence the sides narrow to the broadly 
C. tumidum, Lundell, C. a 
dermum, Lundell, C. cruciatum, Bréb., and C. galeritum, Nordst., all 
of which seem sufficiently obvious] ; Cosmarium monochondrum, D8 
as minute, about as lon 
nembrane smoo d- ate at each 
side, in side-view circular, papillate at each side |; C. phascolus, viet 
truncato-convex, on centre of each fr inent papilla. 
This form thus differs from ae ont surface a prominent ps 
