NOSTOCHACE.E. 



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NOTODELPHYS. 



N. verrucosum, Vaucher. Frond blad- 

 der-shaped, softly leathery, fuscous-green ; 

 filaments spiral, densely entangled, joints 

 globose ; periderm gelatinous, soft, green 

 or dirty brown. On stones in streams. 



N. variegatum, Moore. 



BIBL. The works above quoted; Itzig- 

 sohn, Bot. Zeit.TLii.SZl (1854); Sachs, Bat. 

 Zeit. xiii. 1 (1855) ; Thuret, Mem. Societt 

 de Cherbourg, 1857, Ann. N. H. 3 ser. ii. 1; 

 Kiitzing, Sp. Alg. 295, and Phyc. gen. 204 ; 

 Fischer, Nostoc. 1853 ; Hicks, Qu. Mic. Jn. 

 1861, ii. 90 ; De Bary, Regensb. Fl. 1863 ; 

 Rabenh. Alg. ii. 161. 



NOSTOCHA'CE^E. A family of Con- 

 fervoid Algae, forming gelatinous strata or 

 definitely shaped gelatinous balls or masses, 

 on damp ground or floating at the bottom 

 of water; consisting of minute, unbranched, 

 usually moniliform, microscopic filaments, 

 tranquil or oscillating, imbedded in a mass 

 of mucilaginous or firmish substance (the 

 amorphous matrix is produced by the fusion 

 of the gelatinous sheaths of the individual 

 filaments); filaments finally breaking up. 

 Cells of the filaments of three kinds:!. 

 ordinary cells ; 2. vesicular cells or hetero- 

 cysts, usually large and without granular 

 matter, frequently with erect hairs ; 3. spo- 

 rangia or sporangial cells, produced by the 

 enlargement of the ordinary cells, globular, 

 elliptical or cylindrical. Reproduction by 

 spores has been observed in Cylindrosper- 

 mum by Thuret, who finds that the spo- 

 rangial cells produce in their interior one 

 thick-coated spore, which, after a season of 

 rest, germinates and breaks out from the 

 sporange to grow into a new cellular fila- 

 ment. 



Synopsis of British Genera. 



Nostoc. Phycoma globose or spreading, 

 gelatinous or coriaceous, containing simple, 

 curved, and entangled, moniliform, colour- 

 less or greenish filaments, composed of cells 

 imbedded in a gelatinous matrix ; hetero- 

 cysts globose, interstitial, larger than the 

 other joints. 



Monormia. Frond a gelatinous, elon- 

 gate, curled and convolute sheath, enclosing 

 a single moniliform filament ; heterocysts 

 interstitial ; sporangia developed from j rants 

 most distant from the vesicular cells. 



Trichormus. Heterocysts interstitial and 

 terminal. Sporanges at first formed from 

 the cells most distant from the heterocysts. 



Sphcerozyga. Heterocysts interstitial ; 

 sporanges from the nearest cells. 



Cylindrosporum. Heterocysts terminal ; 

 sporanges like the last. 



Dolichospermum. Heterocysts interstitial ; 

 sporanges of unequal length, and without 

 definite arrangement. 



Aphanizomenon. Heterocysts none (?) ; 

 sporanges usually simple and of unequal 

 length. 



Spermosira. Heterocysts interstitial, 

 single or in pairs ; sporanges as in Trichor- 

 mus. 



Exotic genus : Trichodesmium. 



BIBL. Ralfs, Ann. N. H. 2 ser. v. 321 ; 

 Kiitz. Tab. Phyc. i. 91 ; Thuret, Ann. Sc. 

 Nat. 2 se>. ii. ; Meneghini, Mem. Turin 

 Acad. ser. 2. v. 1843 ; Allman, Mic. Jn. 

 1855; Rabenh. Alg. ii. 161; M'Nab, Qu. 

 Mic. Jn. 1874, 215*; Sachs, Hot. 251. 



NOTA'MIA, Flem A genus of Gernel- 

 lariidse, Cheilostoinatous Polyzoa. 



Char. Cells placed back to back, facing 

 opposite directions ; tobacco-pipe-shaped 

 bird's-heads above each pair. One species : 



N. bursaria (PI. 36. fig. 21). An elegant 

 microscopic object. 



BIBL. Johnston, Br. Zooph. 294 ; Busk, 

 Cat. Polyz., Brit. Mus., 36; Hincks, Polyz. 

 99. 



NOTAS'PIS, Herm. A genus of Ori- 

 batea (Acarina). Cephalothorax with 

 lamellar appendages, tarsi with three 

 homodactyle claws. N. bipilis, common in 

 France. (Murray, EC. Ent. 217 ; Michael, 

 Jn. Mic. Soc. 1880, 177.) 



NO'TEUS, Ehr. A genus of Rotatoria, 

 of the family Brachionsea. 



Char. Eyes absent, foot forked ( = eye- 

 less Brachionus). 



N. quadricomis (PI. 44. fig. 13). Carapace 

 suborbicular, depressed, scabrous, areolate, 

 with four spines in front and two behind ; 

 freshwater ; length 1-10 to 1-70". 



BIBL. Ehr. Infus. 602; Pritch. Infus. 



NOTH'RUS, Koch. A genus of Ori- 

 batea (Acarina). Cephalothorax without 

 lamellar appendages, tarsi with three hete- 

 rodactyle claws. N. spiniger, violet-brown, 

 covered with dirt. N. horridus, in moss. 

 (Murray, EC. Ent. 219.) 



NOTOCHL^E'NA, Brown. A genus of 

 Grammitideae (Polypodiaceous Ferns). 

 Several species; tropical. (Hook. Sun. 

 370.) 



NO'TOCHORD. The new name for the 

 Chorda dorsalis. 



NOTODEL'PHYS, Allm. A genus of 

 Copepodous Entomostraca. 



