SPHAGNOCCETIS. 



[ 700 ] 



SPINAL CORD. 



their brilliant yellow-green colour and the 

 wet, spongy character of the beds they form. 

 The leaves are very interesting microscopic 

 objects. 



Rotatoria are sometimes found in the cells 

 of the leaves. Also upon or within the 

 same, the carious parasitic Rhizopod 

 CMatnydopyxu labt/rmthuloides. This, in the 

 resting-stage, consists of a laminated thick- 

 walled cellulose red or green cell. As the 

 organism grows, it bursts the cell-wall, and 

 the protoplasm issues in the form of nu- 

 merous very slender radiating filaments, 

 along which glide minute fusiform bluish- 

 green amoeboid bodies. It seems to bear 

 analogy with the Myxomycetes. 



BIBL. Wilson, Bryol. Br. 14; Schimper, 

 ~l>tn. Sc. Nat A. i.313; Braithwaite, Mosses-, 

 Archer, Qu. M. Jn. 1875, xv. 107 (Chla- 

 mydopyxia) ; Husnot, Sphag. Europ. 1882. 



SPHAGNOCCE'TIS, Nees. A genus of 

 Jun^ermanniesB (Hepaticse), containing one 

 species, S. (Jung.} Sphagni, an elegant little 

 plant growing over Sphagnum and other 

 mosses on bogs ; attaching itself by long 

 radicles, numerous on the under side of the 

 procumbent, nearly simple stem. The gem- 

 miferous branches only have amphigastria. 



BIBL. Hook. Br. Fl. ii. pt, 1. 113; Br. 

 Jung, pi. 33, and Suppl. pi. 2 ; Ekart, Syn. 

 Jung. pi. 6. figs. 43 & 48. 



SPHENE. See ROCKS. 



SPHENEL'LA, Kiitz A genus of Dia- 

 tonmceae. 



This genus appears to consist of the de- 

 tached frustules of Gomphonema. Kiitzing 

 describes seven species. S. vulgaris (PI. 19. 

 fig. 19). 



BIBL. Kiitz. Bacill. 83, Sp. Ala. 62; 

 Rabenht. Ala. i. 282. 



SPHENODE'RIA, Schlum. A doubtful 

 genus of Arcellina (Rhizopoda). 



It is allied to Euglyphe and Trinema. 



BIBL. Pritchard, 'infusoria, p. 557. 



SPHENOM'ONAS, Stein. A genus of 

 Flagellate Infusoria. Free, surface hard ; 

 flagella two, one long, one short ; a tubular 

 pharvnx. Two species ; freshwater. (Kent, 

 /wf.438.) 



'SPIIEXOSI'RA, Ehr., Kiitz. A genus 

 of freshwater Diatomaceae. DIATOMACE.E:, 

 p. 244. 



S. catena (PI. 17. fig. 26). 



BIBL. Kiitzing, Sp. Alg. 68; Rabenht. 

 Fl. Eur. Alg. i. p. 293. 



SPHINCTOC YS'TIS, Hass.,=CYMATO- 



PLEUBA, Sm. 



SPHINCTRFNA. A genus of Calyciei 



(Lichenaceous Lichens), with little stalk- 

 like excipula and scarcely distinguishable 

 thallus, growing on leave's or Pertusaricc. 

 (Leighton, Lich. FL 38.) 



SPICULA (plural of spiculum). In some 

 of the lower Invertebrata, firmness is given 

 to the body by a kind of internal and 

 external skeleton consisting of a number of 

 curiously shaped microscopic bodies, many 

 of which are of a needle-like form, often 

 containing a cavity, and denominated spi- 

 cula. They are met with in endless variety 

 of form in sponges (see SPONGIDA) (PI. 45, 

 the lettered objects), where they usually 

 consist of silex, some being of carbonate of 

 lime. They also occur as anchors &c. in the 

 Echinodermata (PI. 45. figs. 1 h, i, k, I, and 

 19 a, b, c), the Foraminifera (PL 23. fig. 24), 

 and in some of the Zoophytes (Alcyonium) 

 and Mollusca (Doris), in these instances 

 being calcareous. 



There can scarcely be doubt that spicula 

 are homologous with the elements of shell ; 

 but little or nothing is known of their 

 development. They form very interesting 

 microscopic objects, on account of their 

 remarkable forms. 



To prepare them, the animal substance 

 in which they are contained should be 

 boiled with nitric acid if they are composed 

 of silex, and with dilute solution of potash 

 if they consist of lime-salts. They may be 

 preserved by mounting in Canada balsam. 



They are commonly met with in sea- 

 mud, and as fossils in some rocks. 



SPIDERS. See ABACHNIDA. 



SPILOC^EA, Fr. A genus of Torulacei 

 (Conioinycetous Fungi). S. Pomi occurs 

 upon apples, in contiguous efrused patches, 

 from which the epidermis separates in frag- 

 ments, exposing the simple globular spores, 

 adherent to each other and to the matrix. 



Probably only a state of Cladosporium. 



BIBL. Berk. Br. Fl. ii. pt. 2. 360 ; Fries, 

 Sum. Veget. 482. 



SPILONE'MA, Fries. A genus of Col- 

 lemaceous Lichens. 



Char. Thallus filiform, branched, fruti- 

 culose, granula gonima large, in transverse 

 strata. Apothecia lecideine, lenticular. 

 Spermatia shortly cylindrical. 3 species, 

 on rocks. (Leighton, Lich. Flora, 10.) 



SPINAL CORD.-The spinal cord of 

 man is that part of the central nervous 

 system which extends downwards from the 

 medulla oblongata, occupving much of the 

 vertebral canal, and terminating in a conical 

 extremity at the level of the first lumbar 



