SPIROSTOMUM. 



[ 599 ] 



SPIRULINA. 



10. S. bellis. Filaments 1-480" in diam.; 

 joints equal or twice as long ; spiral bands 

 two or three, lax ; spores somewhat glo- 

 bose; var. /3, spirals condensed (Hass. 

 pi. 24). 



11. 8. pelludda. Filaments 1-840" in 

 diam. ; joints four or six times as long ; spi- 

 ral band lax and slender ; fertile cells ven- 

 tricose; spore globose (Hass. pi. 25). 



12. S. rivularis. Filaments 1-2040" in 

 diam. ; joints three or four times as long ; 

 spiral bands four, broad, dense (Hass. pi. 

 27). 



13. S. curvata (Sirogonium sticticum and 

 breviarticulatum, Kiitz.). Filaments 1-720" 

 in diameter, joints four or five times as 

 long ; spiral bands three or four, slender ; 

 conjugation direct, without a cross branch, 

 approaching Mougeotia (Hassall, pi. 26. 

 figs. 1, 2). 



BIBL. Hassall, Brit. Freshw. Alg. p. 135; 

 Kiitzing, Sp. Alg. p. 437, Tab. Phyc. v. ; 

 Pringsheim, Flora, xxxv. p. 465. 1852 (Ann. 

 Nat. Hist. ser. 2. xi. p. 210); Al. Braun, 

 Verjungung (Ray Soc. Vol. 1853, passim) ; 

 Meyen, Pflanzenphysiologie, iii. p. 422 ; 

 Vaucher, Conferves, p. 37; Agardh, Ann. des 

 Sc. nat. 2 ser. vi. p. 197. 



SPIROSTOMUM, Ehr. A genus of In- 

 fusoria, of the family Trachelina. 



Char. Body ciliated all over, oblong or 

 cylindrical and elongated, without a neck ; 

 mouth spiral, with neither teeth nor a tre- 

 mulous lamina. 



S. ambiguum (PI. 24. figs. 77, 78). Body 

 cylindrical and elongated, colourless, obtuse 

 in front, truncate behind, prolonged ante- 

 riorly beyond and above the mouth. Aqua- 

 tic; length 1-12". 



8. virens. Body oblong, green. Aquatic ; 

 length 1-120". 



Dujardin gives the characters : Body cy- 

 lindrical, greatly elongated, and very flexible, 

 often twisted, covered with cilia arranged 

 upon the oblique or helical striae of the sur- 

 face; mouth situated laterally beyond the 

 middle, at the end of a row of larger cilia. 

 The genus consisting of S. ambiguum, E. 

 and S. ( Uroleptus, JZ.Jfilum ; S. virens being 

 placed as Bursaria spirigera. 



BIBL. Ehrenberg, Infus. p. 332; Dujardin, 

 In/us, p. 514. 



SPIROT.ENIA, Breb. A genus of Des- 

 midiaceae. 



Char. Cells single, elongated, cylindrical 

 or fusiform, straight, entire, not constricted, 

 ends rounded ; endochrome spiral. 



Division oblique. In one species the 



endochrome is spiral at first, subsequently 

 becoming uniform. 



S. condensata (PI. 10. fig. 59). Endochrome 

 forming a single broad band. Length 1-208". 

 Common. 



S. obscura. Endochrome at first forming 

 several spiral threads, afterwards uniform. 

 Length 1-240". 



BIBL. Ralfs, Brit. Desmid. 178. 



SPIRULINA, Link. A genus of Oscilla- 

 toriaceae (Confervoid Algae), consisting of 

 minute spirally coiled filaments immersed in 

 a gelatinous matrix, having an oscillating 

 motion; forming extensive strata in lakes, 

 brackish water, &c. The intimate structure 

 and development of these curious organisms 

 are not yet well understood ; they are sup- 

 posed to increase by the filaments breaking 

 across ; in some the filament appears conti- 

 nuous ; in others it has striae, like the Oscilla- 

 torieae (appearing beaded when badly defined). 

 It does not appear that Ehrenberg' s and 

 Dujardin's genus SPIRILLUM consists of 

 species referable to this genus. Several 

 British species are described. 



1. S. Jenneri (PI. 3. fig. 16). Filaments 

 with striae, 1-6000" in diameter, usually of 

 eight or ten coils, forming a thin aeruginous 

 stratum. 



2. S. (?) Thompsoni. Filaments striated, 

 of rarely more than four coils, then about 

 1-50" in length (from the figure, the diame- 

 ter would appear to equal 1-2000" at least), 

 forming a greenish, then pale blue, finally 

 ferruginous stratum. Anabaina spiralis, 

 Thompson, Ann. Nat. Hist. v. p. 84. 



3. S. tenuissima. Filaments not striated, 

 with close coils; coils 1-9500" in diam., 

 pale aeruginous, forming a pellicle of a rich 

 green colour, ultimately ferruginous (Ralfs, 

 Ann. Nat. Hist. xvi. pi. 10. fig. 1 ; Harvey, 

 Brit. Mar. Alg. pi. 27 C). In brackish 

 pools. 



4. S. Hutchinsice. Filaments not striated, 

 with close coils ; coils from 1-9600 to 1-1080" 

 in diam. ; forming an aeruginous stratum in 

 the sea (Kiitzing, Tab. Phyc. i. pi. 37. fig. 2). 



5. S. oscillarioides (PI. 3. fig. 15). Fila- 

 ments not striated; coils 1-7200" in diam.; 

 lax. Among Oscillatoriae in stagnant pools. 



Spirillum minutissimum and rupestre, 

 Hassall, probably belong here; but the former 

 may be Spirillum volutans of Ehrenberg. 

 These organisms require further investiga- 

 tion. 



BIBL. Kiitzing, Sp. Alg. p. 236, Tab. 

 Phyc. i. pi. 37 ; Hassall, Brit. Fr. Alg. p. 

 277. pi. 75 ; Harvey, Brit. Mar. Alg. p. 229. 



