114 WELWITSCH's AFRICAN FRESHWATER ALG.E, 



We can now add West Central Africa to the distribution of this 

 species, and this, along with its habitats in East Africa and Mada- 

 gascar, still further confirms what Lagerheim has stated with regard 

 to the cosmopolitan nature of the species. 



6. C. ANGUSTATUM (Wittr.) Nordst. in 0/oers. K. Vet.-Akad. Fork. 

 no. 6, 20 (1875). Euastrum bbiale var. angustatum Wittr. in Bih. t. 

 K. Vet.-Akad. Handl. Bd. 1, no. 1, 50, t. iv. f. 8 (1872). Euastrum 

 polare Nordst. in Ofo. K. Vet.-Akad. Furh. no. 6, 37, t. vii. f. 24 

 (1872). A form with the vertical view oblong. Long. 25 /x ; lat. 

 14 fM ; lat. apic. 7*5 /x ; lat. isthm. 4-5 ju, ; crass. 8 /x. 



Huilla. In uliginosis editioribus prope Humpata, Empalanca 

 et LopoUo; May 1860. No. 15. 



7. C. MAXIMUM (Borg.). C. ohsoletum (Hantzsch) Reinsch, 

 subsp. maximum Borg. in Vidensk. Medd. Naturh. Furen. Kjoben., 

 1890, 42, t. iv. f. 37 (1891). C. a C. ohsoleto differt celluHs longi- 

 oribus, multe profuudius constrictis, angulis basalibus spinis 

 brevibus patentibus instructis non submamiilatis. 



Var. MINOR, var. n. (tab. 367, fig. 21). Var. duplo-minor et 

 angustior. Long. 68-5 /a; lat. sine spin. 46 jj., cum. spin. 48-5 jx; 

 lat. isthm. 10 /x ; crass. 29 fi. 



Huilla. Inter Utriculariam, Morro de Lopollo ; April 1860. 

 No. 179. 



C. palustre W. B. Turn, (in A'. Sv. Vet.-Akad. Handl. Bd. xxv. 

 No. 5, 60-1, t. viii. f. 65 & t. ix. f. 1) has some resemblance to this 

 species, but is proportionately broader, has a much broader isthmus 

 like that of C. ohsoletum, and the spines at the basal angles are 

 strongly convergent. 



8. C. LuNDELLii Delp. in Memor. Accad. Sci. Torino, ser. 2, 

 XXX. 13, t. vii. f. 62-64 (1878). C. subcirculare W. B. Turn, in 

 K. Sv. Vet.-Akad. Handl. Bd. xxv. no. 5, 52, t. viii. f. 3 & t. ix. 

 f. 27, 37 (1892). 



Var. ^THiopicuM, var. n. Var. 1^-plo longius quam latius, 

 semicellulis latioribus apicem versus ; a vertice visis late ellipticis 

 polis rotundatis (ut in var. madagascariense West) ; membraua dense 

 et minutissime punctata inter scrobiculos parvos. Long. 71-107 /x ; 

 lat. 61-80 /x ; lat. isthm. 30-33 /x ; crass, usque 54 /x. 



Libongo. Ad margines fium. Lifune ; Sept. 1858. No. 204. 



Forma scrobiculata. Forma plus dense scrobiculata, scrobiculis 

 in medio semicellularum multe majoribus, et isthmo angustiori. 

 Long. 104 jj. ; lat. 82 /x ; lat. isthm. 27 /x ; crass. 52 /x. 



Pungo Andongo. In stagnis prope Anbilla (Coudo) ; March 

 1857. No. 177. 



9. C. Baileyi Wolle, Desm. U. 8. 64, pi. xvi. f. 17, 18 (1884). 

 C. depressum Bail., non (Niig.) Lund. Forma cellulis dente minuto 

 ad angulum basalem uuumquemque instructis. Long. 46 /x ; lat. 

 47 jfx ; lat. isthm. 15 /x ; crass. 23 /x. 



Libongo. Ad margines flum. Lifune ; Sept. 1858. No. 204. 

 Var. ANGOLENSE, var. n. (tab. 866, fig. 20). Var. major, cellulis 

 paullo depressioribus, angulis basalibus truncato-i'otundatis, dente 



