ODONTHALIA. 



[ 550 ] 



(EDOGONIUM. 



ODONTHA'LIA, Lyngb. A genus of 

 Rhodomelaceae (Florideous Algae) contain- 

 ing one British species, O. dentata (PI. 4. 

 fig. 13), which has an irregularly bipinna- 

 titid frond, 3 to 12" long, the main axis and 

 lobes 1-4" wide throughout ; colour deep 

 wine-red, darker when dried. Frond with 

 marginal, stalked, ostiolate, ovate ceramidia 

 with spores, lanceolate stichidia, in which are 

 contained two rows of ternate tetraspores, 

 and aniheridia. 



BIBL. Harv. Alg. 77, pi. 11 A; Phye. Br. 

 pi. 34; Greville, Alg. Br. pi. 13, Kiitz. Phyc. 

 generalis^ 448. 



ODONTID'IUM, Kiitz. A genus of 

 Diatoinaceae. 



Char. Frustules quadrangular, united into 

 an elongated biconvex filament; linear in 

 front view; valves elliptical with transverse 

 continuous striae. Freshwater and marine. 



Differs from Dentioula in the elongated 

 filament, which sometimes, however, con- 

 sists of only three or four frustules ! 



O. turyidulum (PL 17. fig. 14 : o, front 

 view; 6, side view). Valves lanceolate, 

 obtusish; striae on each valve six; fresh- 

 water; length of frustules 1-1720 to 1-570". 



O. tabellaria,Srmth = Staurosira construens, 

 Ehr. (PI. 50. fig. 38). 



BIBL. Kiitz. Bacill. p. 44 ; Sp.Alg. p. 12 ; 

 Smith, Brit. Diat. ii. 15 ; Rabenh. Fl Eur. 

 Alg. i. 116. 



ODONTODIS'CUS, Ehr. A genus of 

 Diatomacese. See COSCINODISCUS. 



Char. Frustules single, lenticular ; valves 

 circular, alike, without nodules, covered 

 with dots arranged either in radiating rows 

 or in excentrically curved lines, and with 

 erect marginal teeth. Three species; fossil 

 and in guano. 



O. eccentricus (PI. 18. fig. 52). 



BIBL. Ehr. Ber. Berl.Ak. 1844, 73; Kiitz. 

 Sp. Alg. 129 ; Pritchard, In/us. 



ODONTOPHORE. A new name for 

 the tongue of the Mollusca; and Radula is 

 another. 



ODONTOTRE'MA, Nvl. A genus of 

 Lecideinei (Lichenaceous JLichens). 



Char. Thallus indistinct. Apothecia 

 black, thelotremoideo-lecideine or gymno- 

 tremoid, naked, at first closed, then dehiscing 

 with a denticulato-ruptured proper margin. 



O. lonyius, Nyl. On old rails. 



BIBL. Leighton, Lich. Flora, 389. 



(ECIS'TES, Ehr. A genus of Rotatoria, 

 of the family OEcistina. 



Char. Single; rotatory organ single, 

 with an entire margin; body attached to 



the bottom of a fixed cylindrical carapace ; 

 eyes two, frontal, red, disappearing in ad- 

 vanced age. 



O. crystallinus (PI. 44. fig. 16). Carapace 

 hyaline, viscid, covered with foreign bodies; 

 freshwater; entire length 1-36". 



Jaws each with three teeth. 



BIBL. Ehr. Inf. 392; Pritchard, Inf.; 

 Davis, Mic. Tr. 1866, 14; Hudson, Jn. M. 

 Soc. 1881, 1. 



(ECIS'TINA, Ehr. A family of Rota- 

 toria (small Melicertte, probably). 



Char. Animals single or aggregate, at- 

 tached to the bottom of a gelatinous cara- 

 pace ; rotatory organ single, with an entire 

 margin. 



A distinct carapace for each animal. . . 1 . CEcittes. 

 Carapaces aggregated into a sphere... 2. Conochilut. 



BIBL. Ehr. In/us. 301. 



(EDE'MIUM, Fr. A genus of Dematiei 

 (Hyphomycetous Fungi). GE. atrum, Corda, 

 consists of dense tufts of brown erect fibres, 

 scarcely branched, and without true septa. 

 The roundish " spores " are sessile upon the 

 sides of the erect filaments. 



BIBL. Corda, Sturm's Devtschl. Fl. 6, 

 pi. 9 ; Fries, Syst. Myc. 344 ; Berkeley and 

 Broome, Ann. N. H. 2 ser. vi. 466. 



(EDIPO'DIUM, Schwagr. A genus of 

 Splachnaceae (Acrocarpous Mosses), some- 

 times included under Gymnostonmm. CEdi- 

 podium Griffithianum, Schwag., the only 

 species, is remarkable for the peculiarly 

 thickened fruit-stalk, whence the name of 

 the genus is derived. 



(EDOGONIA'CE^E. A family of fila- 

 mentous Confervoid Algpe, remarkable for 

 the filaments growing by a peculiar mode of 

 cell-division, accompanied by circumscissile 

 dehiscence of the parent cell, and by the 

 zoospores being formed from the whole con- 

 tents and bearing a crown of numerous cilia. 

 Two genera : 



CEdogonium. Filaments unbranched. 



Bulbochcete. Filaments branched and 

 bearing bristle-cells with a bulbous base. 



BIBL. See the genera. 



(EDOGO'NIUM,Lrnk. (B-o&/m*,Leclerc, 

 Vesiculifera, Hass.). A genus of CEdogo- 

 niaceae (Confervoid Algas). Some (EcJoyc- 

 nia are among the commonest and most 

 abundant of freshwater Algae, occurring in 

 every pond, ditch, or stream, and quickly 

 making their appearance in tanks, aquaria, 

 &c. They may generally be recognized at 

 a glance by the dense and uniform green 

 protoplasm, sometimes filling the cells, 

 sometimes (after dividing) leaving half of the 



