KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 25. N:0 5. 149 



From the tig. of Nouost. 8 b it appears that the sides in vert. view of the 

 form, 3-gona, are very convex and unconstricted at or towards the angles; cushions' 

 broadly cuneate. 



Nordstedt gives the size as long. 18, lat. 27 ,u. 



Xot seen in India. In this, and the above forms, I have copied, for the inöst 

 part, the descriptions of Dr. Nordstedt. 



Indien ni, n. f. Cellulär margine medio rotundatae non emarginatte nec incisae; 3- 

 gonse (f. 4-gona non visa). Wallich Mscr. No. 54 c; »having convex edges. The 

 end view of joint is triangulär and exhibits 3 minute narrowly cuneate hyaline 

 processes at the points of cell-junction», G. C. W. T. XIX, f. 5; the rounded pro- 

 jections are hardly so prominent in my figure as in Wallichs 54 c. In vert. view 

 the sides are convex, contracted somewhat towards the rounded angles. 



Nakoorhyall Tal, G. C. W., 1855. 

 Wallichii, n. f. Cellulae margine centrali elevatai et recte truncata?, crenis vel inci- 

 suris nullis. 



Wallich Desui. Beng. t. VII, f. 5 (not very good!), 6, 8; Mscr. Nos. 54, 74. 

 In this the sides of the 3-angled form in vert. view are as the preceding, but with 

 round, not cuneate, processes at the angles; in the 4-angled form the sides are 

 nearly straight. This form or var. seems to be the analogue in this species of the 

 truncate form in T). Swartzii. Zygospores oval, m em bra ne moderately thiek, smooth. 

 3-gona long. 19—20, lat. 22—25 ,«. 

 4-gona » 20,5—30.5, lat. = long., G. C. W. 



Diam. zygs. 22 X 17.5 fi. T. XIX, f. 4. 



Bengal; Northern India. 



From the various figures in Wallich's Mscr. I feel convinced that few of his 

 Bengalese specimens were laterally crenate, though I think that Dr. Nordstedts 

 dicta upori the crenae in this species, Alg. N. Z. p. 26, are perfectly correct, espe- 

 cially as regards the typical form. In this the specimens of/, major, as figured, 

 were often gently incurved at the sides. The connecting processes or 'cushions' 

 seem liable to variation from narrowly cuneate to circular in shape. 



In the interesting example of this sp. in conjugation seen and figured by me, 

 t. XIX, f. 9, the connection of the cells is more clearlv shown than in Wallichs 

 No. 74 Mscr.; I cannot, however, state clearly to whieh form thev appertain. 



Dr. Nordstedt, Alg. X. Z. 1. c, remarks upon the torsion of the filaments in 

 this genus; for my own part I cannot but agree with Wallich, Desm. Beng. p. 186, 

 that the 'twisting' is hardly to be deemed natural: i. e. »during their unrestrained 

 growth in their native element.: Dr. W. adds, that he had »repeatedlv examined fila- 

 ments . . . without compression of anv kind, in whieh no torsion, or but a slight 

 amount of it, was manifest.» Remarks, therefore, upon the number of fronds in a 

 'convolution' are somewhat doubtful. 



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