118 WELWITSCH's AFBICAN PEESHWATER ALGiE. 



angustioribus quam bases, augulis lateralibus leviter submamillatis; 

 a vertice visie ellipticae polls subacutis ; a latere visje ellipticae ; 

 membrana delicate punctata. Long. 75 /x; lat. 50//; lat. isthm. 

 19-5 /x ; crass. 26 /x. 



Huilla. In uligiuosis editioribus prope Humpata, Empalanca 

 et Lopollo ; May 1860. No. 15. 



This differs from C. se.vamjulare Lund, (in }^ova Acta E, Soc. 

 Scient. Ups. ser. 3, vol. 8, no. ii. 35, t. ii. f. 23) in its larger size, 

 its relatively greater length, and in its unequal hexagonal semicells. 



25. C. SULCATUM Nordst. AJg. Sandvic. 13, t. i. f. 18 (1878). 

 Long. 33 /a; lat. 29 fj^ ; lat. isthm. 8'5 //; crass. 17'5 //. 



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

 1857. No. 177. 



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



26. C. mediogemmatum, sp. n. (tab. 367, fig. 11). C. sub- 

 parvum, 1^-plo longius quam latius, profuudissime constrictum, 

 sinu aperto acutangulo ; semicellula^ hexagouo-ellipticse, granulo 

 prope siuum in margine inferiori utrobique, granulis magnis 6 circa 

 granulum ceutralem in centre apicem versus, granulis duobus 

 inferioribus subminoribus et cum scrobiculis perparvis 5 circa 

 unumquemque ; a vertice visfe ellipticfe polis subacutis, granulis 

 3 ad margiuem et 2 intra marginem ad medium utrobique; a latere 

 visfe globosfe, granulis tribus utrobique apicem versus et granulo in 

 medio juxta isthmam; membrana delicate punctata. Long. 36- 

 38 fj. ; lat. 29-31 /x; lat. isthm. 9*5 /x ; crass. 20 /x. 



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

 1857. No. 177. 



The lateral angles of this species are usually finely granulate. 



27. C. siNOSTEGOS Schaarschm, in Maayar. Tudom. Akad. Math. 

 Termeszett. Kozlemcn. xviii. 266, tab, f. 12 (1883). 



Var. OBTUsius Gutw. in Sprawozd. Komisi/l fizyoqraphic., Akad. 

 Uwirj. rv Krakowie, xxviii. pt. ii. 129, t. ii. f. 13 (1893) ; West & G. 

 S. West in Trans. Linn. Soc. ser. 2, v. 58, t. vi. f. 33 (1895). Long. 

 9"5/x; lat. 10'5 /i; lat. isthm. 1'8 /x ; crass. 6 fx. 



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



28. C. EMARGiNATUM West & G. S. West in Trans. Linn. Soc. 

 ser. 2, V. 58, t. viii. f. 14 (1895). A large form with a narrower 

 isthmus. Long. 17-18-5 /x ; lat. 12-13-5 /x; lat. isthm. 4-8-5-5 fi. 



Huilla. In uliginosis editioribus prope Humpata, Empalanca 

 et Lopollo ; May 1860. No. 15. 



29. C. MINIMUM West & G. S. West, /. c. 58, t. viii. f. 10 (1895). 

 Long. 9-5-10-5 /x; lat. 8-9 /x ; lat. isthm. 3-5 /x ; crass. 4-5-5-5 /x. 



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

 uliginosis editioribus prope Humpata, Empalanca et Lopollo ; May 

 1860. No. 15. Morro de Lopollo ; May 1860. No. 182. 



30. C. EXiGUUM Arch, in Proc. Dubl. Nat. Hist. Soc. vol. iv. 

 pt. i. 49-50, t. i. f. 32-33 (1864) ; Nordst. in K. Sv. Vet.-Akad. 

 Handl. Bd. 22, no. 8, 58, t. vi. f. 12 (1888). Long. 19 ft; lat. 

 11-5 /x ; lat. isthm. 6 /x ; crass. 8-5 /x. 



