86 



THE JOURNAL OF BOTANY 



four of which ai'ose in each mother-cell. Long. cell. 5-6'5 //, lat. 

 4-4-6 /x; long. set. 10-13-5 /x. .(Fig. 2, B-F.) 



7. Ankistrodesmus Spirotaenia, sp. n. (Fig. 3, A and B.) 

 Cellulis solitariis, lihere natantibus, inter algas limneticas repertis, 

 angustissiniis et multe elongatis ; parte mecliana angustissime 

 fusiformi, ad polum unumquemque in spinam 

 longissimam tenuissimam et rectissimam sub- 

 gradatim producta ; chromatophora pallide 

 viridi, taeniformi, spiraliter contorta, anfracti- 

 bus circiter 3^-4, pyrenoidibus nuUis. Long. 

 cell. 171-185 ^/x; lat. max. 2-2-1 /x. 



This curious species occurred sparingly 

 among other limnetic Algge in the surface 

 waters of the canal at Lifford, "Worcestershire, 

 in October, 1910. Its exceedingly narrow cells, 

 drawn out at the apices into fine, straight, 

 spine-like processes of great length, and the 

 nature of the chloroplast, are characters which 

 serve to distinguish it. The chloroplast is 

 rather remarkable, consisting of a rather 

 narrow, pale green band, wrapped spirally 

 round the interior of the widest part of the 

 cell, and having about four complete turns. 

 No pyrenoids were observed. 



It is of a length approaching the Closteri- 

 opsis-type, but differs from all the elongated 

 species of Ankistroclesvms in the spirally twisted 

 chloroplast. 



I would here draw attention to a Diatom, 

 Nitzschia Tcenia W. Sm., from which Anhistro- 

 B I desmus Spirotania differs in being a member 



of the Protococcales, and therefore in the 

 / possession of a chloroplast, in the structure 



and nature of its cell- wall, in the equal dia- 

 ^ meter of its cells when viewed from all sides, 



and many other characters. 'I consider this 

 comparison rather irrelevant, but I institute 

 it purposely after reading certain statements 

 Fig. 3. — A and B, made by Mr. G. I. Playfair. In a footnote to 

 Ankistrodesmus Sjnro- ^^^^ ^^ ^.j^^ most amusing papers which has 

 teHt«, sp.n. : A, outline -\ ,^ t\ -i- i.i • j_i 



of cell • B median por- ^ver appeared on the Desmiaiacea, this author,- 

 tion w'ith' chloroplast. replying to the fact that I had twitted him 

 C, A. falcatus var. with having described a common attenuated 

 ackularis{A Br.)G S species of Nitzschia (N. acicularis) as a Closte- 

 West, an elongated -v i ^i j. t j-i ii -j. 



foi-m A X 600-'''""'^' I'eniarks that 1 was apparently "quite 

 B, X 800; C, X 500. ' unconscious" of having "described and figured 

 the same Diatom, Nitzschia reversa, as Anki- 

 strodesmus nitzschioides, sp. n." In the first place, I must remark 



* G. I. Playfair, " Polymorphism and Life-History in the Desniidiacece," 

 Proc. Linn. Soc. New South Wales, 1910, xxxv. jDart 2, p. 459. 



