ROTIFER. 



[ 558 ] 



SAGO. 



thus in pools, on moist earth, mosses, in 

 gutters, &c., and even in the cells of mosses 

 and algae. 



BIBL. Ehrenberg, Infusoria; Dujardin, 

 Infus.-, Siebold, Vergleich. Anat.; Dalrymple, 

 Phil. Trans. 1849. 331; Huxley, Trans. 

 Micr. Soc. 1852. i. 1 ; Williamson, Micr. 

 Journ. i. 1 ; Pritchard, Infusorial Animalc. ; 

 Vogt, Zoolog. Brief e; Valenciennes, Ann. 

 d. Sc. nat. 1850. 



ROTIFER, Cuv. A genus of Rotatoria, 

 of the family Philodinaea. 



Char. Eyes two, situated upon the pro- 

 boscis ; foot furnished with lateral horn-like 

 processes, and with two terminal toes, giving 

 its end a bifurcate appearance. 



R. vulgaris (PI. 35. fig. 23). Body fusi- 

 form, white, gradually attenuated towards 

 the foot. Aquatic; length 1-48 to 1-24". 



This is one of the commonest of the 

 Rotatoria, and has long been known as a 

 favourite microscopic object under the po- 

 pular name of the wheel-animalcule. The 

 anterior and upper part of the body termi- 

 nates in a proboscis, ciliated at the end, and 

 upon which the eyes are placed; the two 

 rounded lobes of the rotatory organ are 

 placed laterally. Behind, and at the root of 

 the proboscis, is the calcar. 



In R. citrinus, the middle of the body is 

 yellowish, the horns of the foot long, and 

 the eyes round. In JR. macrurus the body 

 is suddenly narrowed into a long foot. In 

 R. tardus the body is gradually attenuated, 

 but somewhat deeply constricted into seg- 

 ments. The species are all aquatic. 



BIBL. Ehrenberg, In/us, p. 484. 



ROTIFERA. See ROTATORIA. 



RUBEFACTION, OF WATER. See WA- 

 TER. 



RUCKERIA. A genus of Compositse. 

 The pericarp possesses HAIRS of an interest- 

 ing structure. 



BIBL. Decaisne, Ann. Nat. Hist. vi. 

 p. 257 (Trans, from Ann. des Sc. nat. 2 ser. 

 xii. p. 251). 



RUELLIA. A genus of Acanthaceous 

 Plants. The testa of the seed of Ruellia 

 formosa exhibits a peculiar kind of HAIR 

 (PI. 21. fig. 21). 



RUST, OF PLANTS. See BLIGHT. 



RYE. The grain of SECALE CEREALE. 

 See STARCH. 



RYTIPHLJ3A, Ag. A genus of Rhodo- 

 melaceae (Florideous Algae), containing four 

 British species, mostly common, having pin- 

 nately-branched, filiform or compressed 

 fronds, transversely striate and reticulated ; 



the articulate axis is composed of a circle of 

 large elongated tubular cells surrounding a 

 central cell, the whole enclosed by a kind of 

 rind of several layers of small coloured cells. 

 Colour mostly dull-red or brown. Fronds 

 from 2" to 4" or 6" high. The ceramidia 

 occur scattered on the ramules of some 

 plants; the antheridia tufted in the same 

 situations on others, and tetraspores (tetra- 

 hedral) occur imbedded in a double row in 

 stichidia, borne on distinct plants. 



BIBL. Harvey, Brit. Mar. Alg. p. 80. 

 pi. 11 D; Grev. Alg. Brit. pi. 13; Derbes 

 and Solier, Ann. des Sc. nat. 3 ser. xvi. 

 p. 275. pi. 35. figs. 11 & 12 ; Thuret, ibid. 

 4 ser. iii. p. 20. 



S. 



SACCOGYNA. A genus of Jungerman- 

 niese (Hepaticacese) founded on the Junger- 

 mannia viticulosa of Linnaeus ; it is remark- 

 able on account of the subterraneous fleshy 

 perianth, in which character and in habit it 

 is allied to Calypogeia. It is found among 

 mosses, especially in alpine districts. 



BIBL. Hook. Brit. Flor. ii. pt. 1. p. 121, 

 Brit. Jung. pi. 60; Ekart, Syn. Jung. pi. 1. 

 fig. 6; Endlicher, Gen. Plant. Supp. 1. 

 No. 472-23. 



SACCULUS, Gosse. A genus of Rota- 

 toria, of the family Ichthydina. 



Char. Eye single, frontal ; body free from 

 hairs, and without a foot ; rotatory organ a 

 simple wreath ; alimentary canal very large ; 

 jaws set far forward, apparently consisting 

 of two delicate, unequal, lateral pieces, and 

 a slender central portion, very evanescent ; 

 eggs attached behind after deposition. 



/S. viridis. Length 1-150"; aquatic. 



BIBL. Gosse, Ann. Nat. Hist. 1851. viii. 

 198. 



SAGEDIA, Fries. A genus of Endocar- 

 peae (Angiocarpous Lichens), consisting of a 

 few anomalous plants, closely related to 

 Endocarpon and Verrucaria. 



BIBL. Leighton, Brit. Angioc. Lichens, 

 p. 21. 



SAGENIA, Presl. A genus of Aspidieae 

 (Polypodioid Ferns). Exotic. 



SAGO. Farinas obtained from a variety 

 of tropical plants are known by this name, 

 but the true East Indian sagoes are ex- 

 tracted from the central part of the trunks 

 of Palm-trees belonging to the genus Sagus, 

 natives of the Moluccas. In PL 36. fig. 23 

 is figured the starch of a sago obtained from 

 the Museum at Kew; but it is uncertain 

 whether this is the produce of a Sagus. Its 



