SPELEROPSIS. 



[ 707 ] 



SPILEROZYGA. 



cell, and swim about as free biciliated zoo- 

 spores, of globular or shortly cylindrical 

 form, from 1-2280 to 1-1680" long, either ; 

 bright red or particoloured red and green, j 

 the point bearing the cilia, however, always ; 

 colourless. After a time they become 

 coated with a cellulose membrane, cease to | 

 move, and grow into a spindle-shaped body, 

 the ends prolonged into hair-like points. 

 The growth appears to be always in the 

 middle, the hair-like points remaining; 

 thus the spindle-shape is retained until the 

 length reaches 1-24' or more, and the first 

 septum appears in the middle of the filament. 



S". annulina (PI. 9. tig. 14) appears to be 

 the only well-known form. It is a rare 

 Conferva, growing on flooded fields ; it 

 does not seem to have been recorded in 

 Britain. 



For Sph. crispa and punctalis, see ULO- 

 THBIX. 



BIBL. Kiitz. Sp. Alg. 362, & Tab. Phyc. -, 

 Braun, Verjihufitng, Ray Soc. 1853, 165; 

 Cohn, Ber. 'Berlin. Ak. 1855 ; Ann. Sc.Nat. 

 4. v. 187 ; Ann. N. H. 2. viii. 81 ; Cienkowski, | 

 Bot. Zeit. xiii. 777 ; Rabenht. Alg. iii. 318. j 



SPH7EROPSIS,Lev. AgenusofSphaa- \ 

 ronemei (Stylosporous Fungi), growing 

 upon stems, &c. ; apparently only stylospo- 

 rous forms of Sphaeriaceous genera. 



BIBL. Fries, Sum. Veget. 419 ; Tulasne, 

 Ann. Sc. Nat. 4. v. 115. 



SPH^EROP'TERIS, Wall. A genus of 

 Dicksonieae (Polypodiaceous Ferns). 8. 

 barbata ; India. (Hooker, Syn. 49.) 



SPH^EROSIRA, Ehr. See VOLVOX. 



SPH^EROTHE'CA. A genus of Sphse- 

 riacei (Ascouiycetous Fungi), closely allied 

 to Erysiphe. S. pannosa is common on the 

 leaves and fruits of a rose ; 8, Castagneij on 

 the leaves of hops &c. (Cooke, Handb. 645 ; 

 Tulasne, Carp. i. 208.) 



SPELEROT'ILUS. A genus of Crypto- 

 cocceae, consisting of cells arranged in rows, 

 connected by mucus, forming a flocculent, 

 variously divided floating layer. S. natans 

 (PI. 3. fig. 21), brownish, in organic liquids : 

 said to purify the water. 



BIBL. Rabenht. Alg. ii. 8; Eyferth, Jn. 

 Mic. Soc. 1881, 97. 



SPH^EROZOS'MA, Corda. A genus of 

 Desmidiaceae. 



Char. Filamentous; filaments flat, fra- 

 gile, their component cells closely united 

 by means of minute (glandular) processes, 

 and deeply divided on each side into two i 

 segments. 



S. vertebratum (PI. 14. fig. 9, front view ; 



fig. 10, side view). Cells about as long as 

 broad ; connecting processes oblique, one on 

 each side. Length of cell 1-1430". Not 

 uncommon in ditches. 



S. excavatum. Cells longer than broad ; 

 connecting processes sessile, two on each 

 side. Length of ceU 1-2570". 



After separation, the cells conjugate ; spo- 

 rangia elliptical. Other species. 



BIBL. Ralfe, Br. Desmid. 65; Rabenht. 

 Alg. iii. 148. 



SPILEROZO'UM. A genus of Radio- 

 larian Rhizopoda. 



It consists of a spherical group of rounded 

 bodies consisting of sarcode witk distinct 

 nuclei, surrounded by a zone of siliceous 

 spiculea, the whole being imbedded in a com- 

 mon gelatinous matrix. The centre of the 

 mass is vacuolated; and the whole often 

 becomes a hollow sphere. (Huxley, Comp. 

 Anat. ; Carpenter, Microscope.} 



SPH^EROZ'YGA, Agardh (Anakena, 

 Bory, BrtSbisson). A genus of Nostocha- 

 ceae, differing from the allied genera only in 

 the sporangia! cells being separated by vesi- 

 cular cells. As the sporangial cells are de- 

 veloped from the ordinary cells, and this 

 gradually, the vesicular cell will appear at 

 certain epochs to have a sporangial cell on 

 one side and an ordinary cell on the other ; 

 but this arises merely from the fact that 

 the sporangial cells are developed singly 

 and successively, first one on one side of 

 the vesicular cell and then one on the other, 

 and so on, to whatever number of adjacent 

 sporangial cells there may be developed on 

 either side of the vesicular cell ; and those 

 nearest the latter will therefore always be 

 the largest, until the whole have acquired 

 the full size. Ralfs describes seven British 

 species. 



* Filaments moniliform; sporangia elongated, 

 not turgid. 



S. Carmichaelii. Filaments with tapering 

 extremities; ordinary joints distinct, sub- 

 quadrate ; sporangial cells oblong ; vesicular 

 cells spherical. Rails, Ann. N. H. 2. v. pi. 

 8. fig. 7 ; Harvey, Phyc. Br. pi. 113 A ; Mar. 

 Alya, 2. ed. pi. 27. fig. D. 



Beloniatorulosa,Carniicha.el ; SpJuerozyga 

 compacta, Kiitz. ; Anabana marina, Bre"bis- 

 son ; Cylindrospermum Carmichaelii. Kiitz. 

 Sp. Alg. 294, Tab. Phyc. i. pi. 99. 



Var. tenuissima, with very slender fila- 

 ments. Forming a tender, very thin stra- 

 tum of a dark or bluish-green colour, on the 

 damp soil of salt-marshes flooded at spring 

 2z 2 



