NEBALIA. 



[ '^54 ] 



NEMASPORA. 



Kiitzing describes 170, some of them, how- 

 ever, belonging to Pinmdaria, Gyrosigma, 

 and other genera. Smith describes thirty- 

 six British species. They may all have been 

 derived from a frustule of a Schizonema or 

 CoUctonema which had escaped from its ge- 

 latinous envelope ! 



The formation of sporangial frustules has 

 been noticed by us in Navicula ainphirhyn- 

 chus, and they are contained in a siliceous 

 sporangial sheath or case. The process is 

 sufficiently illustrated by the figures (PI. 41. 

 figs. 19-24) ; fig. 19, side view of the parent 

 frustule ; fig. 20, front view of conjugating 

 frustules, with young sporangial sheath ; 

 fig. 21, empty mature sheath; fig. 22, crushed 

 empty sheath and parent frustules in situ ; 

 fig. 23, sheath, one parent-frustule and spo- 

 rangial frustule in fi^ont view ; fig. 24, spo- 

 rangial frustule in side view. 



N. cuspidata (PI. 11. fig. 6, side view; 

 fig. 7, front view ; a, hoop). Valves lanceo- 

 late, somewhat rhomboid, acuminate ; aqua- 

 tic; length 1-350 to 1-200". Valves slightly 

 iridescent, no striae by ord. iUum. 



N. didyma (PL 11. fig. 9). Valves elliptic- 

 oblong, slightly constricted in the middle ; 

 marine; length 1-600 to 1-300". Ends 

 sometimes broadly rounded, and the con- 

 striction very deep. 



N. rhomboides. Valves rhomboid-lanceo- 

 late ; colourless and not striated by ordin. 

 ilium.; aquatic; length 1-350''. Striae 85 

 in 1-1000" (Sm.). 



JV. ampMrhynchus (PI. 41. fig. 19, side 

 view ; fig. 22, front view of conjugating frus- 

 tules). Valves linear, or nearly so, suddenly 

 contracted near the produced and obtuse 

 ends; aquatic; length 1-500 to 1-250". 



BiBL. ^vaiih, Brit. Diatom, i. A(y', Kiit- 

 zing, Bacill. p. 91, and Sj). Alg. p. 69. 



NEBALIA, Leach. — A genus of Entomo- 

 straca, of the order Phyllopoda, and family 

 Aspidephora. 



Char. Antennae two pairs, large and rami- 

 form ; eyes two, stalked ; legs twelve pairs, 

 eight branchial and foiu* natatory ; carapace 

 large, enclosing head, thorax, and part of 

 abdomen. 



N. bipes (PI. 14. fig. 28). Marine; body 

 yellowish ; length 3-8". 



BiBL. Baird, Brit. Entomostr. p. 36. 

 NECKERA, Hedwig.— A genus of Hy- 

 pnoid Mosses. 



Elegant little perennial plants, growing 

 on trunks of trees and shady rocks, having 

 stems pinnately branched, bearing compla- 

 nate leaves arranged in eight rows. 



N.complanata, B.uhn.^Hyjmum compla- 

 natum, Hedw. 



N. crispa, Dill., found in mountainous 

 districts, is a large moss, with stems 4 or 6" 

 long or more, growing horizontally from a 

 creeping rhizome. 



NECTRIA, Fries. — A genus of Sphaeriacei 

 (Ascomycetous Fungi), distinguished from 

 true SphcericB by the free, membranous, flac- 

 cid, brightly-coloured perithecia, the pale pa- 

 pilla, and the gelatinous pale nucleus expelled 

 in the form of a drop or of white flocks ; 

 the asci contain eight pellucid spores. The 

 imperfect forms of these plants are described 

 as distinct genera. Thus Tubercularia vul- 

 garis, common on bark of dying or dead 

 trunks, and on dead twigs of birch especially, 

 ripens into N. cinnabarina ; this we have ob- 

 served, and it is probable that other Coniomy- 

 cetous forms will require to be reduced in 

 hke manner. Nectria includes the following 

 Sphcerice of the British Flora : cinnabarina, 

 coccinea, ochracea, aurantia, rosella, citrina, 

 Peziza, sanguinea, episphceria, &c., and se- 

 veral new species are described by Messrs. 

 Berkeley and Broome. 



BiBL. Fries, Summa Veg. p. 387; Berk, 

 and Broome, Ann. Nat. Hist. 2 ser. xiii. p. 



467. 



NEMALEON, Targioni. — A genus of 

 Cryptonemiaceae (Florideous Algae), contain- 

 ing two British species, one, N. multifidum, 

 not uncommon on shells and stones near 

 low-water mark. Its frond consists of a 

 somewhat cartilaginous, simple or once or 

 twice dichotomous cord, 3 to 6" high and 

 1 to 2'" in diameter, of a dull purple colour. 

 The cord consists of a dense axis formed of 

 interlaced longitudinal filaments, clothed 

 with horizontal, dichotomously- branched 

 filaments, moniliform and coloured towards 

 the circumference of the cord. The fruit 

 consists of — X.favellidia, consisting of glo- 

 bular masses of *^ spores" attached singly to 

 the filaments of the periphery (MM. Derbes 

 and Solier say that the single cells arising 

 from the filaments each discharge one spore 

 from the interior, so that they are spore- 

 sacs) ; and 2. of collections of antheridia, 

 consisting of minute hyaline cells seated on 

 the peripheral filaments, exactly correspond- 

 ing to the spore-sacs, but discharging sper- 

 matozoids. 



BiBL. Harv. Br. Mar. Alg. p. 153. pi. 21 

 B, Phyc. Brit. pi. 36 ; Derbes and Solier, 

 A7in. des Sc. nat. 3 ser. xiv. p. 274. pi. 35 ; 

 Thuret, ibid. 4 ser. iii. p. 21. 



NEMASPORA, Fries.— A genus of Me- 



