TREBIUS. 



[ 777 ] 



TRICERATIU^r. 



arable. We have some of the solution which 

 has been kept twelve years in a corked bottle 

 with a piece of camphor, and it is as good 

 as if freshlv prepai-ed. 



TRE'BIUS, Krliyer.— A genus of Crus- 

 tacea, order Siphonostoma, family Caligida). 



Cltar. Head in the form of a large buck- 

 ler, with the large frontal plates destitule 

 of sucking-disks ; thorax three-jointed, seg- 

 ments uncovered ; legs four pairs, with long 

 plumose hairs, fourth pair slender and two- 

 branched; autennfe small, Hat, and two- 

 jointed; second pair of foot- jaws two- 

 jointed, and not in the form of a sucking- 

 disk. 



T. caudutiis. Found upon the body of 

 the skate. Male much smaller than the 

 female. 



BiBL. Baird, Entomostraca, 280 ; Thomp- 

 son, Ann. N. H. 1847, xx. 248. 



TREMATO'DA.— An order of Entozoa, 

 containing the tiukes. See Distoma. 



TREMELLI'NI.— A family of Hymeno- 

 mycetous Fungi, consisting of polymor- 

 phous, often convoluted or lobed, more or 

 less gelatinous masses, growing upon 

 branches or stumps of trees, in crevices of 

 the bark, or on the dead wood. The 

 hymenium extends over the whole of the 

 upper exposed surface, and, from the recent 

 researches of Tulasne, appears to present 

 remarkable characters. The gelatinous 

 substance of these Fungi is composed of 

 ramified filaments, with more or less effused 

 mucilage between them. In Tremella a 

 portion of the filaments terminate at the 

 surface at fu"st in expanded globular cells 

 (PI. 27. figs. 3, 4), which Ijecome divided 

 by vertical septa into fom' somewhat pyri- 

 form cells (bastdia) ; fi'om each of these 

 arises a slender filament {stengma\ which 

 terminates in a slender point tipped with a 

 globular spore (^stylospore or basidiospore) . 

 Other filaments coming to the surface in 

 like manner ramify extensively, with short 

 divergent branches, finally bearing nume- 

 rous minute globular bodies (sjjermatia), 

 solitary or in groups of four, which, hke the 

 basidiospores,f all ofl'and rest on the hymenial 

 surface, involved in jelly, but, imlike those, 

 do not germinate. The basidiospores are 

 about 1-.3000" in diameter, the spermatia 

 about 1-12000". In Tremella mesenterica 

 the surface covered with basidiospores as- 

 sumes a whitish colour, the layers of sper- 

 matia and the jelly are orange. 



In Exidia the production of the basidio- 

 spores is similar ; but the spores are reni- 



form and unilocular, about l-2.')00" long 

 and 1-5000'' in diameter, Spermatia have 

 not been detected. 



In Dacryimjces the basidia are represented 

 by simple clavate or bifurcate branches at 

 the hymenial surface, these terminating in 

 points bearing single reuiform spores ex- 

 hibiting three septa (quadrilocular). In 

 germination some of these spores produce 

 a long filament from each loculus ; others 

 behave difierently, producing the spermatia 

 of the plant, each loculus sending out a 

 short pointed process bearing a globular 

 cellule exactly resembling the spermatia of 

 Tremella. Other examples of Dacrijmyees 

 bear a different kmd of reproductive bodies, 

 apparently representing conidia. In these 

 the peripheral filaments terminate in a mass 

 of many-j ointed Torula-Wke processes, which 

 ultimately break up into the separate joints, 

 (See Dacbymyces.) 



BiBL. Berk. Br. Fl. ii, pt, 2, 215 ; Ann. 

 N. H. 2. xiii. 406, pi. 15. fig. 4 ; Tulasne, 

 Ami. Sc. Nat. S. xix. 193, pis. 10-12. 



TRENTErOH'LIA, Mart. = CJianiran- 

 si'a and Chroolepus sp. 



TREPOM'ONAS, Duj.— A genus of Fla- 

 gellate Infusoria, family Monadina. 



Char. Body compressed, thicker and 

 rounded behind, twisted in front into two 

 narrowed lobes, Avhich are inflexed laterally, 

 and each terminated by a flagelliform fila- 

 ment, which produces a very lively rotatory 

 and jerking motion. 



T. ar/ilis (PI. 32. fig, 6). Body granular, 

 unequal; length 1-1100". In decomposing 

 marsh-water. (Dujardin, Infus. 294 ; Kent, 

 Inf. 300.) 



TRIAR'THRA, Ehr.— A genus of Rota- 

 toria, of the famdy Hydatinsea. 



Char. Eyes two, fi-outal ; foot simply 

 styliform ; body with lateral cirri or fins, 



^lovement jerking. Jaws two; each bi- 

 deutate. 



T. longiseta (PI. 44. fig. 30). Eyes dis- 

 tant, ciiTi and foot nearly three times as long 

 as the body ; length 1-216", 



T. mydacina.' Eyes approximate ; cirri 

 and foot scarcely twice as long as the body, 



T. breviseta (Gosse), Cirri much shorter 

 than the body. 



BiBL. Ehr. Inf. 446 ; Gosse, Ann. N. H. 

 1851, viii. 200; Pi-itchard, Infiis. 



TRICERA'TIUM, Ehr.— A genus of 

 Diatomacefe. 



Char. Frustules free ; valves triangulai", 

 areolar, each angle mostly with a minute 

 tooth or short horn. 



