WELWITSCH's AFRICAN FRESHWATER ALG^E. 175 



58. C. SUBSPECIOSUM Nordst. in Ofc. af K. Vet.-Akad. Fork, 

 no. 6,22, t. vi.f. 13(1875). Long. 69 />i; \&i 51 /x; lat. isthm. 17/^; 

 a form which is most probably var. validius Nordst., but specimens 

 not in a condition for the satisfactory determination of this point. 



Puugo Andongo. In rivulis ; March 1857. No. 105, 



59. C. Welwitschii, sp. n. (tab. 367, fig. 2). C. magnum, 

 circiter 1^-plo longius quam latius, profunda constrictum, sinu 

 aperto extreme obtuso ; semicelhilfe subglobosas latiores basin 

 versus, apicibus leviter depressis, serie verrucarum emarginatarum 

 circiter 19 in ambitu, etiam verrucis magnis conicis supra super- 

 ficiem sparsis (interdum geminatis) ; a vertice visfe subgloboste, 

 seriebus approximatis duabus verrucarum emarginatarum de polo 

 ad polum, verrucis conicis sparsis inter seriem unumquemque et 

 marginem ; membrana inter verrucas dense scrobiculata, Long. 

 98-100 ix; lat. 63-66 fi; lat. isthm. 22-24 fx. 



Huilla. In paludibus exsiccandis; April 1860. No. 176. Etiam 

 inter Utriculariam, Morro de Lopollo ; April 1860. No. 179. 



This handsome species approaches C. Lagerhemianum [Dy- 

 Hphinctium Laqerheimianum W. B. Turn, in K. Sv. Vet.-Akad. Handl. 

 Bd. 25, no. 5 (1893), 43, t. xxii. f. 6] , but differs greatly in its 

 much deeper constriction, in its flattened apices, in the double 

 series of emarginate warts, in the shorter conical warts (not 

 elongated papillae), and in the very densely scrobiculate membrane. 

 In the vertical view the double series of emarginate warts are 

 concave towards each other in the centre, and subparallel towards 

 the poles. 



60. C. sequinoctiale, sp. n. (tab. 365, fig. 11). C. parvum, 

 circiter Ij-plo longius quam latius, leviter constrictum, sinu late 

 aperto et rotundato ; semicelluliB suborbiculares base complanata, 

 membrana granulata, granulis parvis seriebus verticalibus circiter 8 

 (ut visis) ordinatis (in serie unaquaque circiter 7) ; a vertice visse 

 subgloboste granulis subradiatim ordinatis, in ambitu circiter 19. 

 Long. 26 /J.; lat. 15*5 /x; lat. isthm. 10 // ; crass. 14 /x. 



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



This is distinguished from C. orbiculatum Ralfs in its less 

 orbicular semicells, its much broader isthmus, and in its smaller 

 granules with definite arrangement. Compare also with C. qualum 

 [Dijsphincthim qualum W. B. Turn.] . 



61. C. coNTRACTUM Kirchu. in Cohn, Kniptog amen -flora von 

 Schles. Zweit. Bd. 147 (1878) ; Wolle, Desm. U. S. 63, t. 16, f. 1 ; 

 t. 50, f. 24 (1884). Long. 35 /i; lat. 22 /i ; lat. isthm. 105 /x ; 

 crass. 18 /x. • 



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

 1857. No. 177. 



62. C. Oocystidum, sp. n. (tab. 366, fig. 21). C. subparvum, 

 circiter l^-plo longius quam latius, levissime constrictum, sinu 

 minute cxcavato ; somicelluUe late pyramidato-trapeziformes, an- 

 gulis superioribus leviter rotundatis, apicibus latis et rectis, lateribus 

 subrectis (leviter convexis) ; a vertice visa) elliptica?, polls acutis et 

 submamillatis ; a latere visaB quadrato-ovatfe, apicibus trancatis ; 



