WELWITSCH'S AFRICAN FRESHWATER ALG^E. 173 



semicellulffi et supra serie verrucarum minorum alternantum 3 ; 

 a vertice visfe anguste ellipticfe, verruca magna emarginata ad 

 polum unumquemque, verrucis 8 utrobique verrucis mcdiauis 4 

 multe majoribus et rotundatis, seriebus subirregularibus duabus 

 verrucarum minorum intra marginem unumquemque ; membrana 

 dense punctata, cum zona scrobiculorum in semicirculis irregularibus 

 circa series transversas duas verrucarum ordinata. Long. 61 /a ; 

 lat. 68-64 /x; lat. isthm. 18*5 n; crass. 33 [j.. 



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



Tliis is a noteworthy species, the large size of the warts and 

 their arrangement easily distinguishing it from any other ; the four 

 median warts on each side of the vertical view being especially 

 pronounced. 



52. C. bilunatum, sp. n. (tab. 367, fig. 17). C. subparvum, 

 paullo latius quam longius, profunde constrictum, sinu aperto ; 

 semicellulfe late lunat^e, angulis convergentibus et attenuatis ad 

 extremitates submamillatas, dorso multe convexo subsemicirculari 

 crenato (crenis circ. 12), ventre late inflato subundulato angulos 

 versus, seriebus lunatis duabus verrucarum rotundarum de angulo 

 ad angulum ; a vertice visse fusiformi-ellipticae, polis submamillatis, 

 marginibus lateralibus undulatis, seriebus rectis duabus verrucarum 

 depressarum de polo ad polum, verrucis paucis intra marginem 

 lateralem unumquemque. Long. 36 |W. ; lat. 40 fx ; lat. isthm. 9-5 /x; 

 crass. 19 /x. 



Huilla. In uliginosis editioribus prope Humpata, Empalanca 

 et Lopollo ; May 1860. No. 15. 



This characteristic species is nearest in outline to C. j)ra:celsvm 

 W. B. Turn, and C. indicum W. B. Turn. 



53. C. mucronatum, sp. n. (tab. 367, fig. 16). C. parvum, 

 1^-plo latius quam lougius, profundissime constrictum, sinu 

 angusto-lineari ; semicellulfe depresso-semicirculares (non angu- 

 lares), angulis basalibus mucronatis ; a vertice visse anguste 

 oblongffi, polis rotundatis et mucronatis ; a latere visne globosfe ; 

 membrana punctata. Long. 23-25 /x; lat. 27-30 /x ; lat. isthm. 

 5 /i ; crass. 10'5-ll-5 /x. 



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

 Utricular iam, Morro de Lopollo ; April, 1860. No. 179. 



This species is distinguished from C. pseudotaxichondrum Nordst. 

 by its rounded semicells, by the complete absence of granules, and 

 by the oblong vertical view. 



54. C. PSEUDOTAXICHONDRUM Nordst. in Offers. K. Vet.-Alcad. 

 Fijrh. no. 3, 20, t. ii. f. 5 (1877). 



Var. AFRicANUM, var.n. (tab. 367, fig. 14). Var. cellulis minus 

 angularibus et latioribus, serie granulorum 3 juxta ct infra apicem 

 semicellulae uniuscuj usque, annulo punctorum minutorum circa 

 grauulum unumquemque ; a vertice visis granulis 3 in medio utro- 

 bique pyrenoidibus binis in scmicellula unaquaque. Long. 27 /x ; 

 lat. 35 /x; lat. isthm. 9*5 /x ; crass. 17 /x. 



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

 Vtricxdariaw, Morro de Lopollo; April 1860. No. 179. 



