SPfLEROPHRYA, 



[ 706 ] 



SPH^EROPLEA. 



Apothecia terminal, spherical, tlie perithe- 

 cium, formed of the tliallus, closed, dehiscing 

 irregularly. Nucleus globular, internally i 

 floccoso-cartilaginous, the discharged (black) i 

 sporidia crowded in the circumference. 



S. coralloides (fig. 395, p. 463), and S.fra- \ 

 ffile, common on sand-rocks, among mosses. 



S. compactum is rare. The spermogonia 

 occur at the ends of the more delicate 

 branchlets of the thallus. 



BIBL. Hook. Br. Fl ii. pt. 1, 236 ; Leigh- 

 ton, Lick. Fl. 48 5 Tulasne, Ann. So. Nat. 3. 

 xviii. 209. 



SPBLEROPH'RYA, Clap, et Lach. A 

 genus of Acinetina. 



Char. Tentacles simple, radiate ; no sheath 

 or peduncle ; body free. 



S. pusilla, small, spherical; freshwater. 

 (Clap, et Lach. Inf. 385.) 



SPELEROP'LEA, Ag. A genus of Con- 

 fervacese of uncertain position, but proba- 

 bly allied to the Chsetophoracese. It is cha- 

 racterized chiefly by the formation of the 

 spores. The plants consist of simple fila- 

 ments, with long joints, at first containing 

 green colouring-matter excavated by large 

 vacuoles, producing a banded appearance 

 (PL 9. fig. 14 a), the contents in the fertile 

 cells finally resolving themselves into nume- 

 rous spiuulose globular spores arranged in 

 longitudinal rows (b), which become red 

 when ripe. 



The development of the spores of S. annu- 

 lina has been observed by several authors ; 

 and Cohn has published an account of the 

 formation of spermatozoids in distinct cells, 

 exercising a fertilizing function. The fila- 

 ments, which always terminate in pointed 

 hair-like ends, present when actively vege- 

 tating the excavated or banded appearance 

 of the green contents above noticed ; the 

 vacuoles separating the bands of a proper, 

 colourless, mucilaginous coat. When about 

 to produce spores the regularity of the bands 

 vanishes, the vacuoles multiply in number in 

 the substance of the bands, and the contents 

 present the appearance of a green froth with 

 starch-granules scattered through it. After 

 a time a number of green corpuscles, the 

 spores, appear in the median line of the cell ; 

 these assume a stellate shape, with radiating 

 threads of protoplasm connecting them to- 

 gether j they soon appear in pairs, separated 

 by transverse false septa, formed by the 

 flattened vesicles of the vacuoles. The spores 

 gradually become better defined, and the 

 false septa disappear ; then the young spores 

 present themselves as globular bodies, de- 



void at this time of a cellulose coat. From 

 two to six minute orifices are preceptible at 

 this time in the partially softened wall of 

 the parent cell. While these phenomena are 

 occurring in some of the cells, a different 

 change takes place in others. The green 

 bands assume a reddish-yellow colour, their 

 starch disappears, and they are gradually 

 converted into myriads of short stick-shaped 

 bodies, which break apart and u swarin " in 

 vast numbers, filling the whole cell, moving 

 actively in all directions. The gelatinous coat 

 of some of the vacuoles sometimes remains 

 intact ; and these then lie free in the cavity 

 of the cell, and are often carried about by 

 the rapid motion of the corpuscles. Orifices 

 are meanwhile formed in these cells also, 

 through which the stick-shaped bodies 

 (spermatozoids) escape into the water. Their 

 length is about 1-3000". The hinder end 

 now appears somewhat swollen, and they 

 bear two long cilia on the pointed beak in 

 fact resembling the microgonidia of the other 

 Confer voids. Cohn states he has seen them 

 accumulate around the orifices of the spore- 

 cells, enter the cavities of these, and swarm 

 about in the interior, in considerable num- 

 bers, at length adhering to the young spores. 

 These resting-spores then acquire a mem- 

 brane, and under this a second , which is 

 at first smooth, but afterwards presents a 

 spinulose or stellate appearance; the first 

 coat is then thrown off, and a third, smooth 

 coat appears under the stellate coat, closely 

 investing the contents. These conditions 

 resemble those of the spores of SPIEOGYRA 

 and other Confer voids ; Spirogyra, however, 

 retains the outer coat until germination. 

 The green contents of the spores ultimately 

 turn red. Their size and number in a cell 

 vary much. 



Cohn has also observed the germination 

 of these spores, which is interesting in se- 

 veral respects. Their ordinary size is from 

 1-1200 to 1-1500" ; and they present, as 

 above mentioned, two coats, the outer ele- 

 gantly marked ; most authors describe it as 

 stellate ; Kiitzing asserts that it is spirally 

 folded. The real fact is, that it is plaited 

 in the direction of meridians from pole to 

 pole, and thus appears stellate when seen at 

 either pole, marked with lines when seen 

 sideways. The spores do not appear to ger- 

 minate until the spring following their pro- 

 duction. The red contents begin to assume 

 a green colour from the surface inwards, 

 divided into two, then into four or eight 

 portions, which break out from the spore- 



