SUGAR. 



[ 624 ] 



SYNCH.ETA. 



delicate transverse layer, and both contain- 

 ing nuclear elastic fibres ; and within this 

 coat is a layer of longitudinal, unstriped 

 muscular fibres. 



The portion of the ducts traversing the 

 cuticle is spiral. 



It is by no means an easy matter to ob- 

 tain the sudoriparous glands in the entire 

 state. The skin of the palm of the hand or 

 the paw of a dog is best for the purpose ; 

 and before making sections with a Valen- 

 tin's knife, the structure should be mace- 

 rated in a mixture of 1 part nitric acid and 

 2 of water, or in solution of carbonate of 

 potash. 



BiBL. KbWiker, Mikrosk. Anat. u.; Todd 

 and Bowman, Physiolog. Anat. SfC. 



SUGAR. — The crystals of sugar of milk 

 are represented in PL 6. fig. 12, and those 

 of diabetic sugar in PI. 6. fig. 13. 



BiBL. That of Chemistry. 



SULPHUR. See Lime, sulphate of (p. 

 396). 



SURIRELLA, Turpin.— A genus of Dia- 



tomaceae. 



Char. Frustules free, ovate, elliptical, ob- 

 long, cuneate or broadly linear in front view; 

 valves with a longitudinal median line or a 

 clear space, the margins winged, and with 

 transverse or slightly radiating canaliculi or 

 tubular strise. 



It appears that in the valves the margins 

 of the depressions are fused together to 

 form tubular channels open at the ends. 



Kiitzing describes fifty-six species or 

 forms. Smith twenty as British. 



S. hifrons (Ehr. 1833 = S. biseriafa, Breb. 

 and Smith) (PI. 13. fig. 22). Frustules in 

 front view broadly linear, with rounded an- 

 gles; valves elliptic-lanceolate, somewhat 

 obtuse ; alae and canaliculi distinct. Aquatic; 

 length 1-180 to 1-96". 



S. gemma (PI. 13. fig. 21). Frustules 

 ovate ; valves elliptic- ovate ; canaliculi nar- 

 row, inequidistant. Marine; length 1-240". 

 S. splendida. Frustules ovato-cuneate, 

 ends rounded ; valves ovato-lanceolate ; alse 

 and canaliculi distinct. Aquatic; length 

 1-160". 



Compare Tryblionella, and see Dia- 

 tom ace^ (p. 201). 



BiBL. Smith, Brit. Diatom, i. 30; Kiitz. 

 Bacill. 59, and Sp. Alg. 34. 



SWARMING.— This term has been ap- 

 plied by the Germans, from comparison 

 with the swarming of bees, to the remark- 

 able oscillating crowding movements of the 

 zoospores of Confervse, while free in the 



cavity of the parent-cell, and preparing to 

 break forth. The zoospores are hence often 

 called " s warming-spores." See Hydro- 



DICTYON. 



SYMBOLOPHORA, Ehr.— A genus of 



Diatomaceae. 



Char. Frustules single, disk-shaped, with 

 incomplete septa radiating from the sohd 

 angular centre; valves not areolar (under 

 ordinary illumination). Marine and fossil. 



S. Trinitatis (PI. 18. fig. 6). Valves with 

 a triangular umbilicus, the transparent mar- 

 gins of which are crenulate, the rest of the 

 disk covered with six bundles of very fine 

 radiating lines. Diameter 1-220". America. 



Five other species. 



BiBL. Ehrenberg, Ber. d. Berl. Akad. 

 1844. 74; Kiitzing, Sp.Alg. 131. 



SYMPHIOTHRIX, KUtz. = Oscilla- 



TORIA. 



SYMPHYOSIPHON, Kiitz.— A genus of 

 Oscillatoriacese (Confervoid Algae), growing 

 on the ground, &c. S. {Scytonema, Lyngb.) 

 Bangii grows among mosses ; it is of black- 

 ish colour, tufted and bristling, the filaments 

 from 1-9600 to 1-7200" in diameter. 



BiBL. Kiitz. Sp. Alg. p. 324, Tab. Fhyc. 

 ii. pi. 44. 1. 



SYMPLOCA, Kiitz.— A genus of Oscilla- 

 toriaceae (Confervoid Algae), perhaps not 

 distinct from Syfiiphyosijohon. Kiitzing in- 

 cludes here S. Ralfsiana = Osc. Friesii of 

 British authors, <S. lucifuga = Oscill. luci- 

 fuga, Harv., and 8. hydnoides = Calothrix 

 hydnoides, Harvey. 



BiBL. Kiitz. Sp. Alg. p. 270, Tab. Phyc. 

 i. pi. 74-76 ; Harvey, Brit. Alg. 1st ed. 



SYNAMMIA, Presl.— A genus of Gram- 

 mitideae (Polypodaeous Ferns). Exotic. 



SYNAPTA, Eschsch. — A genus of vermi- 

 form Echinodermata, of the order Apoda. 



The species of Synapta, which are not 

 British, are of special microscopic interest, 

 on account of the presence in their skin of 

 remarkable anchor-shaped, calcareous spi- 

 cula, the base of which plays in a perforated 

 plate. These are situated upon minute pa- 

 pillae of the skin, and serve to aid in loco- 

 motion and adhesion. 



These bodies have been formed into ge- 

 nera and species of Polygastric Infusoria by 

 Ehrenberg, the perforated plate constituting 

 a Dictyocha. 



BiBL. V. d. Hoeven, Zoologie, i. 150; 

 Vogt, Zool. Briefe, i. 168 ; Quatrefages, Ann. 

 d. Sc. nat. 2 ser. xvii. 19. 



SYNCHiETA, Ehr.— A genus of Rota- 

 toria, of the family Hydatinaea. 



