THALAMOPORA. 



[ 764 ] 



THECAMONADINA. 



Instead of the biserial form, frequently 

 the shell begins with a triserial arrange- 

 ment of chambers ( Verneuilina, with con- 

 tracted aperture ; Candeina?, with perforate 

 septa). The Verneuiline commencement is 

 often succeeded by the usual two alternating 

 rows (Gaudryina, G. pupoides, PI. 23.iig.48), 

 or by a linear growth with terminal aperture 

 ( Tritaxia). The triserial varieties are some- 

 times twisted. If Vulvulina takes on the 

 linear growth, we have Venilina. 



The early chambers of Textularia and its 

 modifications are not unfrequently coiled 

 (Spiroplecta) . Textularia (&P.) annectens 

 (PI. 23. fig. 52), from the Gault, commenced 

 spirally, proceeded biserially, and ended 

 with uniserial chambers. 



Large Textularice are rarely porous and 

 translucent; they usually become sandy 

 (Plecanium). 



Common in all seas, and fossil in all 

 formations from the Silurian upwards. 



BIBL. D'Orbigny, For. Foss. Vien. 245; 

 Williamson, For. 75 ; Morris, Cat. Br. Foss. 

 43 ; Bronn, Index Pal. art. Text. ; Ehren- 

 berg, Mikrog.; Schultze, Org. Polyth. 62; 

 Carpenter, For. 189; Parker and Jones, 

 Ann. N. H. 3. xi. 91 ; 4. ix. 298, x. 189, 

 196, 259; Brady, Carb. For., Pal. Soc. 

 1876, 130. 



THALAMOFORA, Reuss. A large, 

 subcylindric, zoophytoid Foraminifer, com- 

 posed of superimposed chambers, with laby- 

 rinthic and perforated walls, arranged around, 

 and opening into, a central vertical cavity. 

 Thalamopora exhibits characters of alliance 

 with Polytrema, Carpentaria, Tinoporus, 

 Cymbalopora, and, through the last, with 

 Planorbnlina and others of the Rotalina. It 

 is among the Perforata what Dactylopora is 

 among the Imperforata. (Reuss, Geinifa's 

 Elbthalgebirge, 1872, 139.) 



THALASSICOL'LIDA, Huxley. A 

 family of Radiolarian Rhizopoda. 



Char. Composed of structureless cysts, 

 single or aggregate, containing cellular ele- 

 ments and sarcode, giving off' radiate pseu- 

 dopodia, which sometimes run into each 

 other and form a network. Nucleus present, 

 but no contracting vesicle. Numerous yel- 

 low cells occur scattered through them ; 

 and occasionally a few may be seen suspended 

 within the external gelatinous structure. 



The whole organism is permeated by spicula, 

 or sustained by a fenestrated shell. The 

 most common genera are Splicer -ozoum, Col- 

 losphcera, and Thalassicolla. They are ma- 

 rine, in tropical and subtropical seas. 



BIBL. Huxley, Ann. N. H. 2. viii. 1851, 

 489; Qu. Mie. J*. iv. 1856, 72; Miiller, 

 Thalass.', Haeckel, Radiolarien, 1862 ; Wal- 

 lich, Ann. N. H. 1869, iii. 97. 



THALES'TRIS, Claus. A genus of 

 Copepodous Entomostraca. Ten species, 

 marine. (Brady, Copep., Ray Soc. ii. 120.) 



THAMNO'LIA, Ach. A genus of Cla- 

 dodei (Lichenaceous Lichens). 



T. vermicularis ; on mossy earth ; rare. 

 (Leighton, Lich. Fl. 74.) 

 " THAMNOM'YCES, Ehr. A genus of 

 Sphseriacei (Ascomycetous Fungi). It has 

 distinct asci and sporidia. (Berk. Br. Flor. 

 ii. pt. 2. 284; Fries, Sum. Veg. 382.) 



THAUMAN'TIAS, Eschscholtz. A 

 genus of Campanulariidse. 



Char. Stem simple (or branched ?), rooted 

 by a thread-like stolon ; cells campanulate ; 

 polypes with a funnel-shaped proboscis ; re- 

 production by free medusiform buds. 



T. inconspicua, Forbes. Common off the 

 Hebrides. (Hincks, Hyd. Zooph. 178.) 



THAUMATONE'MA, Grev. A genus 

 of Diatomaceae. (Grev. Mic. Tr. 1863, 76.) 



THECA. A term used very loosely in 

 the descriptions of Cryptogamic plants. In 

 the case of the Lichens and Fungi it is syn- 

 onymous with Ascus, a sac in which free 

 spores are developed ; these are called theca- 

 spores or ascospores, in contrast with BASI- 

 DIOSPORES or stylospores. In the higher 

 Cryptogamia, as Ferns, &c., it is used in the 

 sense of sporangium. 



THECAMONADI'NA, Duj. A family 

 of Infusoria (=Cryptomonadma and some 

 Astasiaea, E.). 



Char. Usually coloured ; covered with a 

 non-contractile tegument, which is either 

 hard and brittle, or membranous; locomotive 

 organs one or more flagelliform filaments. 



Many are Algee, or their spores. They 

 are minute, usually green, but some are red ; 

 and they often colour stagnant water from 

 existing in vast numbers. They are mostly 

 recognizable by their rigidity and the uni- 

 formity of their motion. 



Dujardin subdivided them thus : 



A , i' Body ovoid or j Tegument hard and brittle 1. Trachelo 



"globular ( Tegument membranous 2 



lliform 



Two 



Cryptomonas. 



with a tail-like prolongation 3. Phacus (Euglena pt., E.) 



folia'ceous 1 ; without a prolongation 4. Crumenula. 



(Two similar filaments 5. Diselmis (Chlamidomonas, E.). 



fil ml fa -, ne flagelliform filament, and j Body prismatic or boat-shaped 6. Ploeotia. 



8- / one trailing retractile filament J Body ovoid or pip-shaped 7. Anieonei 



Several filaments Body prolonged into a point in front " *~ 



Anisonema. 

 Oxyrrhit. 



