KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 25. N:0 5. 143 



In 1885 I made my last gathering at Strensall, before the destruction of the 

 place by drainage (up to that it was a prinneval bog!), and inter alia I found this 

 form, which I noted. On comparing in 1886 with a form from Northern India I 

 found it the same. Noticing also the form I have described as S. vinculatum, I was 

 in doubt as to which of these I should refer to S. Jiliforme, this plant having, between 

 the processes, the larger foramen or opening, as usually aeeepted for this Desmid, 

 while the form of the cells theniselves in the other are more like Ehrenberg's figures 

 loc. cit. I consulted Arceier's notes, he says, »It is distinguished from S. excavatum 

 by the elliptic form of the segments separated by an acute constriction and by its 

 larger size; and from S. vertebratum by the double, not single, processes conneeting 

 the joints. It is smaller than the latter, and not so bright a green in colour»; A. in 

 Dubl. M. Club. Proc, Xov. 1868. But the little Onychonema I described (0. Xord- 

 stedtianum) answers this description equally well! Wolles description seems good, 

 but unfortunately he does not figure the minide details in lus t. IV, f. 5, 6, Desm. 

 U. S. Amer., giving the diameter as 12 — 18 /u. My English specimens were smaller 

 than the Indian ones, lat. and long. 15 X 12 fi\ Lundell gives lat. = long., 11 — 12 

 V. Eiirexbergs dimensions in Meteörp. 1. c. (calculated according to Meneghini on 

 ineasurement' in Sull. Anim. Dia t., 1853) give long. 10. c fi\ while Kutzing records 

 the length as 13.5 ,«. I do not regard the fäet of the sinus being more or less open, 

 or the semicells ranging from oval to elliptic, as of great moment — these plants 

 being so subject to such variation; what is required is an authoritative criticisin on the 

 dorsal processes, and such valid criticisin I cannot find! The best suggestion is that of 

 Xordstedt, (Desm. Borhh. pp. 208, 213, 1388), upon Cookes figures in his Br. Desm., 

 t. II, f. 6, »that a forms (i. e. with ovate semicells) >yet more resembling the figure 

 of Ehrexberg than that of Turner appears to have beeu discovered.» Of the Strensall 

 specimens (3) two were smooth, and one minutely and linearly granulate, in the ori- 

 ginal drawing the sinus is not so open as in the Indian specimens figiired, but more 

 so than in ( 1 ookes icons l. c. However, the note under S. vinculatum supra, and its 

 figure, raay be considered in connection with this form; vide page 142. 



In 1887 Nordstedts opinion was (Alg. N. Z. p. 29) that my Onychonema 

 Nordstedtkahwn should be O. jiliforme (Eiir.) R. and B. (Jap. Desm. p. 242); but in 

 18S8 he considered that the identitv was an open (piestion, being doubtful thereon. 

 I have therefore fcépt the plants separate. 

 10. S. sp. 



Long. 11—12; crass. 7—8 u. T. XVIII, f. 19. 



Probably the side view of an unknown species. 



The Spluerozosmata may be subdivided by the differences in their lateral mar- 

 gins, thus: 



A. SphiiTozosnia (sensu ( 1 ordano). Lateral margins rounded or sub-angular. 

 Typ. sp. S. vertebratuin, hliforme. 



B. Temnozosnia (Ttfivco, seco; läiö/xa, cingulum). Lateral magins truncate, plane or 

 incavate. 



