( 'osmarium ] xi. dbsmidi l< i b | w i 351 
This is somewhat lik<- C. nitidulum !>«■ N. I in Form, ba! the ven 
thick and Bcrobiculate membrane easily distinguishes it. 
15. C. trifossum W. el G. 8. West in J. hum. Bot. 1897, p I 16, 
t. 367, f. 19. 
Hi ii i \. Enter Utriculariam, Morro «!-• Lopollo ; Apr. I 
N". 179. En paludibus exsiccandis ; April I860. No 176. Etiam in 
graminosis paludoxis jnxta rivulum de Lopollo ; April I860. No 180. 
Tin' threi' shallow notches Been in th<- front view of each Remicell 
are due to the presence of three grooves running at righi angles to 
both the longitudinal and transvei 3< 
16. C. galeritum Nordst. in Vidensk. Medd. Naturb. I 
Kjoben. 1869, No. I 1 15, 209 210, t. iii. f. 26 - 1870); V, 
s. West in Journ. Bot. 1897, \>. 1 Hi. 
Libongo. Ad margines flum. Lifune ; Sept 18 - \'<>. 204. 
17. C. nitidulum \,,t. Desm. [tal. 12, fc. iii. f. 26 | L867). 
C. rectosporum W. B. Turn, in K. Sv. Vet.-Akad. Bandl. Bd. 
. 5, 69, t. v t. 16 ( 1893). 
V:ir. minor W. el < r. 8. West, I.e. 
Hi in \. [n palndibns exsiccandis ; April I860. N". 176. 
18. C. scenedesmus help, in Memor. Accad. Sci. Torino, ser. 2, 
xxx. 5 6, i. vn. f. 28 :;i (1878). 
Var. dorsitruncatum Nordst. in K. Sv. Vet.-Akad. Handl. Bd. 
xxii. no. 8, 59, fc. iii. f. L5 I 1888); W. el G. S. West, I.e. 
A small form with a perfectly smooth membrane. 
Hi ii. i \. En paludibus exsiccandis ; April I860. X". 176. 
Libongo. Ad margines flum. Lifune ; Sept. 1858. Xn. 204. 
L9. C. aethiopicum W. el G 8. West in Journ. Bot. 1897, 
p. 1 16, t. 367, f. 20. 
Pi ngo Andongo.- Inter Scytonema Myochrou* ▼. chorograph 
Dichotrichtm gypsophilam ad latera boreal, et occid. de Pedra Songue ; 
April 1857. No. 12. 
Hi [lla. Inter Poiphyrosiphonem Notarisi prope Lacum Evantala : 
March I860. No. 17. 
In outline this species calls to mind C. rectangidart Grun. 1868 
i C. Gotlandicum Wittr. 1872), but the more angular semi-cells, the 
much broader isthmus, anil the plications present on the upper half of 
the Bemi-cells. at once distinguish it. 
•_'<». C. pseudoprotuberans rZirchn. in Cohn, Kryptog. floi 
Schlesien, Zweit. Bd. 150 (1878); Nordst. in Of v. K. Vet.-Akad. 
Forh. no. 3, 8, b. vii. f. 3 (1885); W. el G. 8. West, Lc, p. 117. 
A small form agreeing with vax, pygmatum Gutw. (Flora 
glon6w okolic Lwowa, 54, t. ii. f. 9) in dimensions, but of the 
same form as the I ype. 
IImu.a En paludibus exsiccandis ; April 1860 X". 176. 
21. C. polygonum A.vli. in Pritch. [nfua 732(1861) 
Euastrum polygonum Nag. Gatt. Einz. Alg. 120, t '< \.i. 9 (1849). 
Var. exile W. el G. s. Weal in Journ. Bot. 1897, p. N7. 
