70 W. B. TLRNER, FRESH-WATER ALG^; OF BAST INDL\. 



tumidae; membrana subtiliter et dénse punctata; sinn acuto triangwlari, externe eon- 

 stricto fere oeeluso. A vertice visum ovali-ellipticum apicibus attenuatuin sub-den- 

 tatum. Zygospora globosa, processubus brevibus capitatis munita. 



Long. 25, lat. 32, lat. isth. 10, crass. 11 — 14, diam. zyg. c. acul. 46, s. acul. 

 33 u (sec. Wallich Mscr. Nos. 169 et 176). T. XIX, f. 13,' 16x700. 



Apparently nearest to Nos. 16 and 69 of this memoir; it is a member of the 

 series containing C. obsoletum, Hantzsch; C. éllipticum, Delp., ete. 



115. C. promillens, n. sp. C. minutum, quarta parte longius quam latius; semicellulaj 

 ovales, granulum vel tubereulum unicum in ventre habentes; membrana glabra; sinn 

 triangulari, acuto, externe valde ampliato. A vertice visum ovale; a latere modiee 

 constrictum, incisura mediana sub-acuta, semicellulae globosse. 



Long. 15, lat. 12, lat. isth. 4—5, crass. 9 u (also Wallich Mscr. No. 154). 



T. X, f. 7. 



The front and lateral views are inueh like C. biocidatum Bkéb. var. ompholum 

 Schaar. (Des. Hung. p. 270, t, I, f. 9), but the vertical aspect differs in being 

 broadly oval. 



116. €. nmbonatum, n. sp. C. minutum, eire. V 2 longius quam latius, octagonum; semi- 

 cellulae sub-quadrata', basi rötundatae, angulis superioribus ca>sis; angulis lateribus 

 apicibusque incavato-sinuatis; semieellula^ in centro paullo tumescentes, tubereulo 

 unico instruetie; membrana glabra; sinn profundo, lineari. A vertice visum ellipti- 

 cum; a latere modiee constricta?, semieellulis sub-globosis. (Forsan (i umhonatuiu 

 C. Meneghinii ?) 



Long. 13, lat. 9, lat. isth. 4, crass. 7 u (also Wallich, Mscr. No. 156). 



»These tubercles do not appear to be eonstant, as some sjiecimens, having exaetlv 

 the same dimensions, and with the other characters similar, are deticient in these 

 appendages,» G. C. W. 



Ti X, f. 10. 



117. C. Camhricum, Cooke and Wills (in Grevillea, p. 91, 1880) f. minor. 



Long. 25, lat. 17, lat. isth. 7 ,«. T. X, f. 15. 



This species is separated from C. venustum Bhéb. with some doubt: the only 

 difference being that the sides of C. camhricum are more regularlv inelined to the 

 apex, and the undulations are smaller than in the other species. 



118. C. venustum, Bréb. (Liste, p. 124, t. I, f. 8), formse: 



Long. 19, lat. 12, lat, isth. 4 ,«. T. X, f. 20. 

 » 28, » 17.5, » » 4 » » » f. 24. 



The latter is very near to Didym. (Cosm.) Brauni, Eeinnch (Algenfl. p. 116, 

 t, X, f. III e), the truncate forms of which are but forms of C. venustum. It is 

 interesting to note that Lundeli, (Desm. Suec. \). 23) has observed a filamentous 

 form of this speeies. 



forma? Long. 21, lat. 14.5, lat. isth. 4 ,//. T. XI, f. 2. This has the 



apices faintly retuse. 



forma? Long. 2ö, lat, 14, lat. isth. 4.5 ti. T. X, f. 19. 4'hese two plants 



niudi reserable each other, exeept lliat the latter is longer and more attenuate; pos- 



