THELIDIIM. 



C 765 ] 



THYRSOPORELLA. 



BIBL. Dujardin, Infus. 323. 



THELID'IUM, Mass. A genus of Micro- 

 lichens parasitic on the thallus of Lecanorae. 



Char. Spores subfusiform, 2-locular, co- 

 lourless. (Lindsay, Qu. Mic. Jn. 1860, 346.) 



THELOCAR'PON, Nyl. A genus of 

 Pyrenodei (Lichenaceous Lichens). 



Four species. (Leightou, Lich. Fl. 439; 

 Lindsay, Qu. Mic. Jn. 1869, 345.) 



THELOTRE'MA, Ach. A genus of Pla- 

 coidei (Lichenaceous Lichens), containing 

 two British species. (Leighton, Lich. Fl. 

 238.) 



THEO'RUS, Ehr. A genus of Rotatoria, 

 of the family Hydatinaea. 



Char. Eyes colourless, more than three, 

 cervical, in' two groups; foot forked; jaws 

 each with a single tooth 



T. vi'rnalis (PI. 44. fig. 32). Toes small, 

 frontal hook absent. Aquatic; length 1-140 

 to 1-120". 



T. uncinatus. Toes long, frontal (or 

 rather cervical) region with hooks ; fresh- 

 water ; length 1-240". 



BIBL. Ehr. Inf. 454 ; Pritchard, Inf. 690. 



THLIPSU'RA, J. & H. A Cytheroid 

 Ostracode in the Silurian strata. (Jones 

 and Holl, Ann. N. H. 4. iii. 213.) 



THO'REA, Bory. A genus of Batra- 

 chospermeae (Confervoid Algae), of which 

 one species (T. ramosissima) occurs in Bri- 

 tain ; its fronds are olive-black, branched 

 filaments, a foot or more long, about as thick 

 Fig. 740. 



Thorea ramosissima. 



Horizontal section of a filament (halved). The semi- 

 circular denser portion represents the axis, the loose 

 spreading branches the villi. Magnified 25 diameters. 



as a crow-quill, with a villous surface. The 

 filaments are composed of radiating branched 

 cells, closely compacted into a kind of solid 

 axis, from which proceed lax, radiating ra- 

 niuli, forming the yillous surface. The 

 spores or sporangia! cells arise from these 

 ramules (fig. 740). 



BIBL. Kiitz. Phyc. yeneralis, pi. 16, Sp. 

 Alff. o-,4 ; Enij. But. Supp. No. 2f>48 ; Has- 

 sal], Alg. 64; Rabenht. AJg. iii. 418. 



THOREL'LIA, Boeck. A genus of 

 Copepodous Entomostraca. T. brunnea, on 

 Lamitutria. (Bradv, Copep. i. 9o.) 

 ' THUIA'RIA, Flem. A genus of Polypi, 

 of the Order Hydroida, and family Sertula- 

 riidae. 



Char. Those of Sertularia ; but the cells 

 closely pressed to or imbedded in the stem 

 or branches. Two species : 



T. thuia. Cells ovate-elliptical, acutish ; 

 vessicles pear-shaped. On shells from deep 

 water. 



T. articulata. Cells ovate, obtuse or trun- 

 cate, vesicles elliptical ; rare. 



BIBL. Johnston, Br. Zooph. 83; Gosse, 

 Mar. Zool. ii. 23; Hincks, Hyd. Zooph. 



THU' JA, L. A genus of Coniferee (Gym- 

 nospermous Plants), to which belongs the 

 arbor vitce of gardens, Thuja occidentalism 

 T. orientalis is placed by some authors under 

 another genus, Biota. The characters of 

 Coniferous wood, Gymnospermous ovules, 

 &c., may be observed in these plants (see 

 CONIFERS and OVULE). 



THURAM'MINA, Brady. A subglobu- 

 lar Arenaceous Foraminifer (0-5 mm.), with 

 perforate papillae; single and enclosing a 

 smaller chamber or group, and adherent. 

 Atlantic and Pacific. (H. B. Brady, Q. Jn. 

 M. Sc. n. s. xix. 45.) 



THURIC'OLA, Kt. A genus of Peritri- 

 chous Infusoria. Like Vaginicola, but sheath 

 with a closeable valve. Three species ; salt 

 and fresh water. (Kent, Inf. 718.) 



THY'AS, Koch. A genus of Hydrachnea 

 (Acarina). Like Hydrachna, but legs formed 

 for walking. T. venusta. (Koch, Uebers. ; 

 Murray, EC. Ent., fig.) 



THYMELEA'CE^E. An order of Di- 

 cotyledons to which the Spurge-Laurels 

 (Daphne) belong. In D. Lagetto ( = Lagetta 

 lintearia) the fibres of the liber are separated 

 into lozenge-shaped meshes, arranged in 

 such beautiful and easily-separable layers, 

 as to have acquired for the plant the name 

 of the LACE-BABK TREE. 

 See LIBEB. 



THYRSOPOREL'LA, Giimb. Giimbel 

 divides the Dactyloporideee (see DACTYLO- 

 PORA) into (I.) those with chambers: 

 1. Haploporella ; segmented, annular, or 

 cylindrical (piled rings), with large cham- 

 bers and simple traversing canals (6 species, 

 recent and Tertiary) : 2. Lactyloporella ; 

 cylindrical, with large and subsidiary cham- 

 bers, and branched traversing canals (4 

 species, Tertiary). (II.) Those without 

 chambers : 3. Thyrsoporella ; cylindrical 



