GONGROSIRA. 



[ 301 ] 



GONIOI. 



into long fragile Fig. 286. 



filaments ; endo- 

 chrome simple, un- 

 dulate and twisted. 

 2 species ; fresh- 

 water. 



G.Ralfsii(P\M. 

 fig. 37). 



BIBL. Raben- 

 horst, Flor. Alg. iii. 

 p. loo. 



GONGROSl'RA, 

 Ktz. A genus of 

 Chaetophoraceae 

 (Conf ervoid Algae). 



Gonatorrhodon speciosum. 



Fertile filaments with swollen joints bearing chains of 

 spores. Magn. 100 diams. 



Filaments jointed, sub-dichotomously 

 branched or tufted, attenuated at the base to 

 form a root-like thread; joints as long or 

 twice as long as broad, torulose. Four 

 species ; minute ; on stones, wood, and 

 aquatic plants. (Rabenhorst, Fl. Alg. iii. 



GONID'IA. The name applied to cells 

 which in the Thallophytes perform an office 

 analogous to that of the GEMMAE of the 

 higher Cryptogams, and the separating bud- 

 structures such as bulbils, stolons, &c. of the 

 Flowering Plants, being cells developed 

 from the vegetative tissues, ultimately 

 thrown off, and capable of propagating the 

 individual. The gonidia of the Lichens are 

 globular cells with green contents, developed 

 in the central lay ers of the thallus, afterwards 

 set free by the destruction of the cortical 

 layer; they appear capable of multiplication 

 by subdivision before growing out into the 

 filaments which form the foundation of the 

 new thallus (see LICHENS). And the en- 

 dochrome has lately been observed in a few 

 Lichens to be resolved into zoospores, a cir- 

 cumstance which brings Lichens in an im- 

 portant point still nearer to Fungi. The 

 gonidia of the Fungi are usually termed 

 CONIDIA (see that article, and FUNGI}. The 

 gonidia of the Algae are best known in the 

 CONFEBVOIDS, where they are formed from 

 the cell-contents, and generally present 

 themselves ciliated, as ZOOSPORES. The 

 tetraspores of the Florideae are probably 

 the homologues of gonidia. 



GONIO'COTES, Nitz. A subgenus of 

 Philopterus, like Goniodes, but the antennae 

 alike in both sexes. 



G. hologaster, on the fowl. 



GONIOCY'PRIS, R & R. A minute 

 Ostracode, with yellowish, compressed, trian- 

 gular valves ; found in the rivers and dykes 

 of Eastern England. 



BIBL. Brady and Robertson, Ann. N. H. 

 1870, vi. 15. 



GONIO'DES, Nitzsch. A subgenus of 

 Philopterus (Anoplura), distinguished by 

 the large head, with projecting temporal 

 angles, no trabeculae ; antennae f orcipate in 

 the males, cylindrical in the females. 

 Several species, on the turkey, the guinea- 

 fowl, the domestic fowl, the pheasant, and 

 the grouse. 



GONIOM'ONAS, St. A genus of Fla- 

 gellate Infusoria. 



Char. Free, or adherent posteriorly; 

 flagella two, equal, obliquely truncate in 

 front. 



G.truncata. Freshwater. (Kent, Z??/.280.) 



GONIONE'MA, Nyl. A genus of Bys- 

 saceous Lichens. 



G, velutinum. On subalpine rocks ; rare. 

 (Leighton, Lick. Fl. 9.) 



GONIOTHE'CIUM, Ehr. A genus of 

 fossil Diatornaceae. 



Char. Frustules terete, with a median 

 (longitudinal) constriction (suddenly atte- 

 nuate and truncate at the ends, hence ap- 

 pearing angular). 



Corresponds to Pyxidicula, constricted in 

 the middle, and truncate at the ends. 



Found in America. 



We have figured several of the nine or 

 ten species, some of which do not appear to 

 have the characters of the genus. 



G. Anaidus (PI. 61. fig. 18) ; G. barbatum 

 (fig. 19) ; G. didymum (fig. 20) ; G. mono- 

 don (fig. 21); G. navicula (fig. 22); G. 

 Rogerm (fig. 23) ; G. gastridium (PI. 50, 

 fig. 40) ; G. odontella (fig. 44). 



BIBL. Ehrenberg, Abh. Berl Ak. 1841, 

 401, Berl. Ber. 1844, 82, and Mikrogeol. ; 

 Kiitzing, Bacill. 51, and Sp. Alg. 23; 

 Greville, Mic. Tr. 1865, 56. 



GO'NIUM, Miiller. A genus of Volvo- 

 cineae (Confer void Algae), forming micro- 

 scopic, square, flat fronds, either ciliated and 

 endowed with a power of motion, or devoid 

 of cilia and motionless ; it is possible that 

 these two conditions are only stages of deve- 

 lopment in species active at one time and 

 resting at another. The perfect fronds are 

 composed of usually sixteen cells, enclosed 

 in wide colourless coats (young fronds but 

 four cells, some kinds have more than six- 

 teen) united together into flat square masses 

 by adherence at various points of their cir- 



