230 MESSES. "W. WEST AND G. S. WEST ON 



Genus Gonatozygon, De Bary. 

 1. G. ACTJLEATUM, Hastings, in Amer. Month. Micr. Journ. (1892) p. 29. 



Porma minor. (PI. XIL figs. 1, 2). G. mediocre, diametro 8-12-plo longius, cylin- 

 dricum, sed ad polos leviter dilatatum ; membrana spinis longis rigidis numerosis 

 obsessa. 

 Long. 125-160 ^i ; lat. ad med. 14-15 n, ad pol. 15-17-5 ^i ; long. spin. 5-5-7'5 ^i. 

 This was noticed by us some years ago, but only iu single cells, and although an out- 

 look has been kept for it ever since, no filaments have yet been found. 



Mr. Hastings [l. c.) proposes to call a Gonatozygon which he found, G. aculeMum ; 

 this is most probably the same species that we have observed. The G. pilosum figured 

 by W. B. Turner (Preshw. Alg. of E. India, pi. 20. figs. 1, 2) may be a more slender 

 variety of this species ; it is certainly not like the G. pilosum, WoUe, we have seen. 



Genus Phzmatodocis, Nordst. 



2. P. NoRDSTEDTiANA, Wolle, Pesm. U.S. p. 28, pi. 49. figs. 1-4. 



Porma minor, Boerg. in Vidensk. Meddel. 1890 (1891), p. 25 et fig. xylogr. 

 Long. 33-38-5 ^ ; lat. 27-34-5 ^i ; lat. isthm. 11-5-15 ^^. (PI. XII. figs. 3-0.) 

 In all the specimens observed the apices of the cells were a little narrower than across 

 the middle ; this is also shown in the figures given by Nordstedt of var. novizelandica 

 (Preshw. Alg. of New Zeal. & Austr. pi. 2. figs. 1, 2). The lateral margins are also less 

 imdulate than either the example figured by Wolle or that given by Boergesen ; the sinuses 

 also, although somewhat open, are not ampliated like either of the above-mentioned 

 figures. Nordstedt, in Ofvers. Sv. Yet.-Akad. Porh. (1877) n. 3, p. 19, in his definition of 

 the genus, states that the filaments are not twisted ; Wolle says they are " not at all or 

 only slightly twisted " ; our specimens are distinctly twisted (as much as a Desmidiumy 



Genus Sph^rozosma, Corda. 



3. S. AuBERTiANUM, West, in Journ. Bot. xxvii. (1889) p. 206, t. 291. fig. 17; in 



Journ. Linn. Soc. (Bot.) xxix. (1892) p. 115, pi. 19. fig. 1. Zygosporse globosse 

 vel subglobosse, aculeis longis curvatis basi latioribus cum papilla obtiisa intra basin 

 uniuscujusque spinae, 

 Piam. zygosp. sine spin. 19-24 /u, cum spin. 37-5-42 n. (PI. XII. figs. 7, 8.) 

 Hab. Orono, Maine. 



S. Archerii, Gutw., in Sprawozd. Akad. Krak. xxvii. ii. (1892) p. 29, 1. 1. fig. 4, differs from 

 S. Aiihertianum only in having two transverse series of granules across the semicells in 

 addition to the two at the margin. Purther specimens examined show that S. Aubertiamm 

 has often a few additional granules within the margin of the semicells ; moreover, the 

 zygospores we have recently found correspond exactly to those of S. Archerii, Gutw. 

 As the latter species was described some years later and differs so little from S.Aubertimmm, 

 we place it under this species as var. ArchejHi nobis. 



S.fiUforme, W. B. Turn. Preshw. Alg. of E. India, p. 142, t. 18. fig. 20, seems to us 

 very near this variety, but has a more open sinus. 



