STAUROPTERA. 



[ 614 ] 



STENTOR. 



Striae resembling those of Navicula, or 

 intermediate between those of Navicula and 

 Pinnularia ; often invisible by ordinary 

 illumination. 



The species or forms are numerous ; 

 Kiitzing describes forty, Smith admits ten 

 British species. 



S.pha>nicenteron(P\. 11. fig. 43). Valves 

 lanceolate, gradually attenuated towards the 

 somewhat obtuse ends; stauros reaching the 

 margins of the valves; striae faint. Aquatic; 

 common; length 1-170". 



S.pulchella (PL 11. figs. 44, 45). Valves 

 oblong, ends obtuse; frustules in front view, 

 broadly linear, constricted in the middle, and 

 rounded-truncate at the ends; striae distinct; 

 stauros not reaching the margins. Marine ; 

 length 1-70". 



BIBL. Ehrenberg, Ber. d. Berl Akad. 

 1843 ; Kiitzing, Bacill. p. 104, and Sp. Alg. 

 89. 



STAUROPTERA, Ehr. A genus of Dia- 

 tomaceae, including those species of Stauro- 

 neis in which Ehrenberg was enabled to 

 detect the transverse striae ; it is no longer 

 retained. 



STEARIC ACID. The crystals of this 

 fatty acid are represented in PL 7- fig- 166. 

 BIBL. See that of CHEMISTRY. 

 STEMONITIS, Gled. A genus of Myxo- 

 gastres (Gasteromycetous Fungi), consist- 

 ing of little, somewhat stamen-shaped plants, 

 either separate or fasciculated, growing on 

 rotten wood, &c. They appear at first in the 

 form of a mucilaginous flocculent expansion 

 (fig. 700), from which the membranaceous 



Fig. 700. 



Stemonitis ferruginea. 

 Mycelium overgrowing decaying pine-leaves. 



peridia grow up (fig. 701). Many of these 

 remain abortive, others are raised upon 

 stalks, ripen, and on the separation of the 

 fugacious peridium, display themselves some- 

 what in the form of DIACH^EA, but with a 

 bristle-like columella and no remains of the 



peridium. The flat, cylindrical or globose 

 Fig. 701. 



Stemonitis ferrug'mea. 



Immature (fasciculate) peridia arising from the myce- 

 lium. 



reticulated capillitium is penetrated partly 

 or through its whole length by a columella 

 continuous with the peduncle; the spores 

 are interspersed in the reticulations of the 

 capillitium. Capillitium and spores mostly 

 of blackish colour. There are numerous 

 British species ; S. fusca is common. See 

 ENERTHENEMA and DIACH^A. 



BIBL. Berk. Brit. Flor. ii. pt. 2. p. 317, 

 Ann. Nat. Hist. i. p. 257, vi. p. 431. 2nd 

 ser. v. 366; Greville, So. Crypt. Fl. pi. 170; 

 Fries, Summa Veg. p. 455, Syst. Myc. iii. 

 p. 156. 



STENOGRAMME, Harv. A genus of 

 Rhodymeniaceae (Florideous Algae), contain- 

 ing one very rare British plant, 8. interrupt a, 

 characterized by stalked, flat, fan-shaped 

 fronds, more or less divided dichotomously 

 into riband-like lobes, 3-5" high, of a clear, 

 pinky-red colour. It is composed of a central 

 layer of large, globular cells, with a kind of 

 rind of small cells. The conceptacles form 

 a sort of sorus or dark line resembling a 

 rib up the centre of each fertile lobe. Tetra- 

 spores and antheridia unknown. 



BIBL. Harv. Brit. Mar. Alg. p. 123. 

 pi. 15 D. 



STENTOR, Oken. A genus of Infusoria, 

 of the family Vorticellina. 



Char. Body conical or trumpet-shaped, 

 free, or sessile and attached by the narrow 

 base; covered with cilia; anterior portion 

 widened and fringed with a marginal row of 

 longer cilia, with a spiral row of cilia extend- 

 ing from it to the mouth. Aquatic. 



These Infusoria are among the largest and 

 the most beautiful in the class. The body 

 is very contractile and liable to variation in 

 form, often becoming ovate, oblong, or glo- 

 bular. The so-called nucleus is moniliform 

 or strap- shaped. The encysting process has 

 been noticed in some of the species. 



S. Mullen (PL 25. fig. 3). Body colour- 

 less unless from containing foreign coloured 

 particles, with a fringe of cilia or a ciliated 

 crest extending from the mouth to near the 



