Plewrotcemum] \i. dbbmidiacea (W< 343 
2. P. Ehrenbergii De I'm. Oonj. 78 i I 
Docidium Ehrenbergii Breb. (1844); Ralfs, Brit. Deem. 157, 
t. x.wi. f. I 1 1848) ; W. el G. 8. Weel in Journ. Bot. I 397 
l*i noo Andongo. — In Btagnia prope Anbilla (Condo) M 
No. 177. 
3. P. maximum Lund, in Acta R. Boc. Scient. CTps. -■,-. 3, viii. 
n<>. ii. 89 (1871); W. el G. 8. vVesl in Journ. Bot. 1897, p 
Docidiwm maxim/urn Eteinsch in Abhandl. Senckenb. Natui 
Geeellsch. vi. L40, t. xx. C ii. f. I 2 I L866 7,; in Abhandl. 
Nairn lii-i. i tesellsch. zu Nurnberg, iii. L84, i. \ii. t. I (IS 
Libonoo. Aci margines tliiin. Lif nne ; 8ep1 1858. No. 204. 
The shorter Bemicells (which are BometimeB only 175 n in Length) 
have only one basal inflation ; the longer ones have two 
7. ICHTHYOCERCUS W. el G. 8. Wesl in Journ. Bot. 1897, 
p. 80. 
1. 1. angolensis W. el G. 8. West, le. t t. 368, t. 26 31. 
Hi ii. i. v.— In uliginosia editioribua prope Humpata, Erapalanca 
et Lopollo, plagas Bpongiosas unacum Briocauloneis, Xyridibus et 
Utriculariis constituena ; May I860. No. 15. Cn gramiuosis paludoais 
juxta rivulum de Lopollo ; April L860. No. 180 Morro de Lopollo; 
May L860. No. 182.' 
This genua Beems to be mar Tetmemorus and Euastrum. It re- 
Bemblea the former in it- elongate form, in being but slightly con- 
Btricted m the middle, and in possessing a circular (or very Dearly 
circular) vertical view ; it differs from ii. however, in the absence of 
the deep linear notch at the apex, in the presence of a Bpini 
apical angle, and in the general conformation of the upper half <>f the 
semicells, which are somewhat wed^e shaped, with convex surfaces. 
From Euastrum it differs in its very slight constriction, its more 
parallel sides in front view, and in its circular vertical view. 
The cell membrane appears t<> he much less firm than that <>f a 
Tetmemorus. The punctulationa on it are in .-(.me -p., 
and in other- distant from each other, and occasionally the] 
well developed at the apical angles as to give them a faintly rough 
appearance. In one example the spine at cue df the apical angles 
was duplicated, the two spines being placed close together, and of 
differenl lengths. 
[t also approaches the genus Triploceros, bul the delicate character 
of tlie membrane, which is also destitute of warts, and the Bomewhat 
different apex distinguish it. 
8. TETMEMORUS Half- (1844). 
1. T. granulatus Elalfs in Ann. Mag. Nat. lli-i. \i\. 257, \. viii. 
f.2(1844); Brit. Desm. L47, t. xxiv. F. 2, t. xxxiii. f. 1 (1848 . 
W. ,.i <:. s. \\c. -i in Journ. Bot. 1897, p. 81. 
( 'h.stt rin in graniUatum Breb, (18i 
Hi mi \ Int.r Ujtriculariam cymbantham, Morro de Lopollo; April 
No. 179. 
2. T. laevis Ralfs, Brit. Desm. I f.. t. vdv. F. 3 | L€ 
Ciosterivm Usve Kiitz. Phyc. Germ. L32 (184 
