SPIROSTOMUM. 



[ 718 ] 



SPLACHNACE^E. 



shells of S. naidiloides (communis) (PI. 36. 

 fig. 29) are frequently met with upon Fucus 

 serratus, &c. The animal has six pinnate bran- 

 chial filaments and a pedunculate operculuna. 



SPHtoS'TOMUM, Ehr. A genus of 

 Heterotrichous Infusoria, family Bursarina. 



Char. Body ciliated all over, oblong or 

 cylindrical and elongated, or flat ; mouth 

 spiral, with neither teeth nor a tremulous 

 lamina ; anus posterior ; freshwater. 



S. ambiguum (PL 31. figs. 77. 78). Body 

 cylindrical and elongated, colourless, ob- 

 tuse in front, truncate behind, prolonged 

 anteriorly beyond and above the mouth ; 

 length 1-12". 



S. teres. Body linear-fusiform ; length 1-60' '. 



BIBL. Ehr. Inf. 332; Dujard. Inf. 514; 

 Clap, et Lach. Inf. 231. 



SPIROT^E'NIA, Brdb. A genus of 

 Desmidiacese. 



Char. Cells single, elongated, cylindrical 

 or fusiform, straight, entire, not constricted ; 

 endochrome spiral. 



Division oblique. In one species the 

 endochrome is spiral at first, subsequently 

 becoming uniform. 



S. condensata (PI. 14. fig. 59). Endo- 

 chrome forming a single broad band ; length 

 1-208" ; common. 



S. obscura. Endochrome at first forming 

 several spiral threads, afterwards uniform ; 

 length 1-240". 



BIBL. Kalfs, Desmid. 178 ; Archer, Qu. 

 Mic. Jn. 1867, 186 ; Rabenhorst, Alg. iii. 

 145. 



SPIRULI'NA, Link. A genus of Oscil- 

 latoriaceae (Confervoid Algae), consisting of 

 minute spirally coiled geeen filaments im- 

 mersed in a colourless gelatinous matrix, 

 and having an oscillating motion ; forming 

 extensive strata in lakes, brackish water, 

 &c. The intimate structure and develop- 

 ment of these curious organisms are not yet 

 well understood; they are supposed to 

 increase by the filaments breaking across : 

 in some the filament appears continuous; 

 in others it has striae, like the Oscillatorice, 

 appearing beaded when badly defined. 



S. Jenneri (PI. 7. fig. 16). Filaments 

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

 eight or ten coils, forming a thin aeruginous 

 stratum. 



8. oscttlarioides (PI. 7. fig. 15). Fila- 

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

 lax. Among Oscillatorice in stagnant pools. 



BIBL. Kiitzing, Sp. Alg. 236; Hassall, 

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

 pi. 27; Phyc. -Br.pl. 105; Ralfs, Ann. N.H. 



xvi. 308, 2. viii. 205; Cohn, Nova Acta, 

 xxiv. ; Rabenht. Alg. ii. 90. 



SPLACHNA'CE^E. A family of Funa- 

 rioideae (Acrocarpous operculated Mosses), 

 of broad and densely tufted habit, mostly 

 found upon dung, with a very much branched, 

 loosely-leaved stem (fig. 669). Inflorescence 

 hermaphrodite, dioecious, rarely monoecious. 

 Antheridial flower a capituliform, terminal 

 bud. Antheridia large, club-shaped, rather 



Fig. 669. Fig. 670. 



Splachnum vaseulosum. 

 Fig. 669. Nat. size. 



Fig. 670. Eipe capsule open, dried, and the apophysis 

 shrivelled. Magnified 20 diameters. 



Fig. 671. Fig. 672. Fig. 673. 



Splachnum vaseulosum. 



Fig. 671. Calyptra. Magnified 20 diameters. 



Fig. 672. Young capsule and apophysis. Magnified 

 20 diameters. 



Fig. 673. Vertical section of an unopened capsule with 

 its spongy apophysis. Magnified 20 diameters. 



curved. Archegonia narrow, long-apicu- 

 late. Peristome, if present, of regularly 



