FRONTONIA. 



[ 336 ] 



FUCACE.E. 



men from the Chalk, closely allied to the 

 typical Fr. complanata, Defr. 



BIBL. D'Orbigny, For. Foss. 67; Wil- 

 liamson, Itec. For. 23 ; Morris, Br. Foss. 35 ; 

 Reuss, Bohm. Kreid. ; Carpenter, Introd. 

 For. 160, 164. 



FRONTO'NIA, Ehr. A genus of Infu- 

 soria, of the family Bursarina (Cl. & L.). 



Char. Resembles Ophryoglena, except in 

 the absence of the watch-glass organ. 



Most of the species of Dujardin's genus 

 Panophrys belong here. 



F. leucas (Bursaria L, Ehr.). Parenchyma 

 armed with trichocysts ; buccal fossa oval, 

 pointed behind j a single contractile vesicle. 

 Freshwater. 



BIBL. Ehrenfeerg, Inf. 329; Clap, and 

 Lachm. In/us. 259. 



FRULLA'NIA,Raddi. A genus of Jun- 

 germannieae (Hepaticae), containing three 

 British species, the Jungermannia Hutchin- 

 SICB, dilatata, and Tamarisci of Hooker's 

 British Flora. F. dilatata is very common, 

 creeping on the bark of trees, its dark brown 

 dry foliage appearing like minute spreading 



Fig. 251. 



Frullania Tamarisci. 



Portion of a stem, with branches bearing the perichsetes 

 from which the sporanges emerge. 



Magn. 5 diams. 



blotches; the almost sessile capsules are 

 somewhat inconspicuous, but are distin- 

 guished by their whitish colour. The valves 

 of the capsule and the elaters afford beauti- 

 ful microscopic objects, illustrative of the 

 spiral structures in cells. F. Tamarisci 

 (fig. 251) has longer and more regularly pin- 

 nate stems, forming large lax tufts on the 

 ground and low bushes, chiefly in Subalpine 

 countries. 



BIBL. Hook. Brit. Jungerman. pis. 1, 5, 6; 



Brit. Flora, ii. pt. 1. 128 ; Endlicher, Gen. 

 Plant. Suppl. i. No. 472-10. 



FRUSTU'LIA, Ag. A genus of Diato- 

 macese. 



Char. Frustules naviculoid, free or irre- 

 gularly scattered through an amorphous 

 gelatinous mass ; valves elliptic-lanceolate, 

 without central and terminal nodules ; lon- 

 gitudinal line interrupted in the middle. 

 Freshwater. 



F. salina, Ehr. Frustules in front view 

 very narrowly linear, rounded at the ends ; 

 valves suddenly acute at the ends ; trans- 

 verse stria) evident; gelatinous envelope 

 continuous; length of frustules 1-2200 to 

 1-864". Found in a saline spring. 



This organism is of particular interest, 

 as having formed the subject of Schmidt's 

 ultimate analysis, in which he determined 

 the presence of cellulose. (DIATOMACEJE, 

 p. 249.) 



F. membranaceay nobis (PI. 50. fig. 6). 

 Frustules in front view linear, very slightly 

 narrowed towards the ends ; valves lanceo- 

 late, constricted near the obtuse ends; 

 length of frustules 1-1250". 



Found abundantly forming a thin stratum 

 or film upon the sides of a glass jar con- 

 taining water-plants. 



F. saxonica, Rab. (PL 19. fig. 17). Frus- 

 tules in front view linear, rounded at the 

 ends ; valves elliptical, somewhat acute. 



Forms dirty olive-brown, gelatinous, tre- 

 mulous masses, contained in small pits in 

 rocks. 



This is sometimes used as a test-object. 

 It is regarded by Dallinger and others as 

 the same as Navicula rhomboides and crassi- 

 nervis. 



Rabenhorst describes 5 species ; one 

 fossil. 



BIBL. Ehrenb. In/us. 232 ; Kiitzing, 

 Bacitt. 109 ; id. Sp. Alg. 96 ; Rabenhorst, 

 Fl. Alg. i. 227 ; Hickie, M. M. Jn. 1876, 

 xv. 122 : Stodder, ibid. 253 : Dallinger, ibid. 

 1877, xvii. 1, 173. 



FUCA'CE^E. A family of Fucoideaa. 

 Olive-coloured inarticulate sea-weeds, whose 

 reproductive organs are borne in stalked sacs 

 upon the walls of spherical cavities excavated 

 in the substance of the frond. Fructification, 

 sporanges or spore-sacs and antherid'ia. The 

 spores of Fucus divide into two, four, or 

 eight within the sac ; those of the other 

 genera remain undivided. The antheridia 

 are filled with spermatozoids or anthero- 

 zoids, which in FUGUS have been seen to 

 fertilize the spores. See Fucus. 



