GONOTHYR.EA. 



[ 3G2 ] 



GRAMMATOXEMA. 



cumference. A light vacuole in the suh- 

 stance of the cell-contents may often he ob- 

 served to exhibit a rhythmical con*:raction 

 arid expansion, as in Vo/vo.r. The cells of 

 the active forms have each a pair of vibratile 

 cilia, which run out from the central proto- 

 plasmic mass, through the b^'aline envelope, 

 and project as free processes, rowing the 

 frond about in the water. They are com- 

 monly observed to increase by division, a 

 frond composed of sixteen cells breaking up 

 into four fronds, each composed of four cells, 

 &c. ; but it is probable that other kinds of 

 development exist, and that the motionless 

 forms are resting states of active species. 

 Gonium pectorale is an exceedingly interest- 

 ing microscopic object, not uncommon in 

 freshwater pools. 



G.pedorale (PI. 7. tig. 11). Frond square, 

 composed of sixteen bright-green cell- 

 masses enclosed in hyaline envelopes, each 

 with a pair of cilia ; size of green masses 

 1-1960 to 1-1150"; frond not exceeding 

 1-280". In clear water, salt and fresh, 

 near the surface. 



G.imncialum. Cells sixteen; cell-masses 

 green, with black granules ; diam. 1-4600" ; 

 frond of sixteen, 1-576". 



G. tranqniUum (PI. 7. fig. 12). Cells 

 sixteen ; cell-masses green, diam. 1-2880" ; 

 frond of sixteen, 1-144 to 1-288", some- 

 times twice as broad as long ; the cell-masses 

 found in division (biuate or quaternate), 

 motionless. (Possibly not a Gonium, but a 

 Palniellacean — Tetraspora P). 



G. hyalinum. Cell-masses hyaline, diam. 

 1-3000"; frond of twenty or twenty-five, 

 1-600". In stagnant water. 



G. fjlaucmn. Cell-masses bluish gi'een, 

 from four to sixty-four in a frond, diam. 

 1-7000 to 1-4200"", ditto of frond not ex- 

 ceeding 1-570". In sea-water. 



BiBL. Ehrenberg, Inf. 55 ; Cohn, Nova 

 Acta, xxiv. 109, pi. \^ ; Fresenius, Mtis. 

 Setickenh. Gesell. ii. 187, 1856. 



GONOTIlYRyE'A, Alhnan.— A genus 

 of Oampanulariidse, Hydroid Zoophytes. 

 2 species. 



G. Loveni (Laomedia dichotoma, John- 

 son), on the fronds of the large sea-weeds, 

 and on stones, at low-water mark. 



BiRL. Hincks, Hydroid. Zooph. 180. 



GOli'DlUS, Linii. — A genus of Nema- 

 toid Entozoa. 



Char. Body veiy long and slender, fili- 

 form ; alimentary canal (none, Vill.) with a 

 single orifice, sexes distinct. 



G. aquations, the common hair-worm, is 



from 7 to 10" in length and about 1-25 to 

 1-20" in breadth, of a brown or blackish 

 colour, and is found in water or damp 

 places. The mouth is very indistinct ; the 

 tail of the male is bifid, that of the female 

 simple and rounded. 



The ova, agglutinated in long strings, are 

 deposited in water, and being devoured by 

 insects or Arachnida, undergo development 

 within their bodies. 



These animals frequently coil themselves 

 into a knot-like form, whence the name. 



See Mermis. 



BiBL. Dujardin, Helminth. 290, and Arm. 

 So. Nat. 1842, xviii. 142 ; Ent,. Zcit. 1842 

 -43, and Erichson's Archiv, 1843, ii. 302 ; 

 Berthold, Ban d. Wasserkulbes, 1842 ; 

 Meissuer, Sieh. Sf Koll. Zeits. 1856, i. ; Sie- 

 bold, ibid. 141 ; Grenadier, Sieh. S^- Koll. 

 Zeitsch. 1868 ; Villot, Ann. N. H. 1872, x. 

 231 ; Compt. Rend. 1880, 1569 ; Ann. N.H. 

 1880, vi. 160. 



GORGO'NIA, Linn.^ — A genus of marine 

 Polypi, of the order Actinoida, and family 

 Gorgoniadffi. 



Char. Polypidom rooted, and consisting 

 of a central, branched, horny, and sometimes 

 anastomosing flexible axis, coated with a 

 soft and fleshy pohqiiferous crust. 



The species are popularly known as sea- 

 fans; they are not microscopic, often attain- 

 ing very considerable dimeui^ions. 



The polypidom, as well as the crust, con- 

 tains spicula of .various forms imbedded in 

 them, a specimen of which is exhibited in 

 PL 41. fig. 27. 



BiBL. Johnston, Brit. Zooph. 166 ; Kent 

 (spicules), M. M. Jn. 1870, 76 ; Gosse, Adi- 

 noloqia. 



GOSSYPIUM. See Cotton. 



GOUT-STONES. See Chalk-stones. 



GRACILA'RIA, Grev.— A genus of 

 Rhodymeniaceae (Florideous Algae), with 

 feathery fleshy-cartilaginous fronds, 3 to 

 12" or more long, of a red or purplish colour, 

 the central substance of which is composed 

 of large cells, the cortical of closely packed 

 horizontal filaments. The spores are formed 

 in tubercles consisting of a thick coat com- 

 posed of radiating filaments, containing a 

 mass of minute spores on a central placenta. 

 The tetraspores are imbedded in the cells of 

 the surface. G. eonfervoides is the only 

 conmion species; it grows from 3 to 20" 

 long, and as thick as small twine. 



BiBL. Ilarvev, Br.Mar.Aly. 128,pl.l6C; 

 Em/l. Bot.f\. 16(J8. 



GRAMMATONEMA, Ag.— A genus of 



