T.EXITIS. 



[ 751 ] 



TARGIONIA. 



The old genera Cccnurus, Cysticercus, and 

 EC/H'HOCOCCUS are the larval or nurse-forms 

 of Tcenia. 



BIBL. Weinland, on Tape-worms ; Som- 

 mer, Geschlechtsory. v. T. sol. fy mediocanel- \ 

 lut a ; Mejrnin, Compt. rend. 1870, 88, Ann. 

 X. 11. 1870, iii. 317; Piutner, Bau fyr. 

 1880; Moiiiez, Cestodes, 1881; Stein, Ent- 

 icick. n. Parasitism, menschl. Cestoden, 1882. 



TyENITIS,Sw. A genus of Gramniitidese 

 (Polypodiaceous Ferns). Five species; tro- 

 pical". (Hooker, Syn. 300.) 



TALC. See MICA. 



TAO'NIA, J. Ag. A genus of Dictyo- 

 taci'se (Algie), containing one rare British 

 species, T. a/omaria, which has a flat, mem- 

 branous, fan-shaped, deeply cleft frond, 

 3 to 12" high, of brownish olive colour; 

 marked on both faces, at intervals of 1-4 to 

 1-2", with concentric wavy lines, formed by 

 rather crowded dark-brown lt spores," the 

 interspaces being dotted over with scattered 

 spores. The disk of attachment is covered 

 with woolly filaments. 



BIBL. Harvey, Mar. Alg. 38; Thuret, 

 Ann. Sc. X. 4. iii. 7. 



TAPIIPJ'NA. A very low form of As- 

 coinycetous Fungi, formerly included under 

 EUINKUM, to which genus E. aureum, on 

 Poplar, and E. clandestinum, on Hawthorn, 

 are now referable. (Tulasne, Ann. d. Sc. 

 N. ser. v. ; Greville, Crypt. Fl.} 



TAPHROCAM'PA, Gosse. A genus of 

 llotatoria, of the family HydatiiiEea. 



Char. Rotatory organs absent ; body fusi- 

 form, annulose, tail forked, gizzard oval. 



T.anmdosa. Freshwater; length 1-110". 



BIBL. Gosse, Ann. N. R. 1851, viii. 100; 

 Pritchard, Inf. 002. 



TAPIOCA. A very pure fecula prepared 

 from the liner particles of the starch of the 

 Mandioc or Cassava plant (PI. 40. fig. 14). 

 The starch-granules of tapioca of the shops 

 appear to have undergone the action of 

 heat, which disguises the characters. See 

 STARCH. 



TAHDIG'RADA (Water-bears). An 

 Order of Arachnida. 



These microscopic animals are found in 

 stagnant fresh water, amongst water-plants, 

 in patches of wet moss, in the gutters of 

 houses, &c. 



Body soft, cylindrical or elongate -oval in 

 outline, with four transverse furrows or in- 

 distinct segments, and a fifth anterior, cor- 

 responding to a head, short, conical, retrac- 

 tile and with indications of two or three 

 segments ; some times dilated at the end to 



form a sucker, or furnished with unequal, 

 short, palp-like processes. Eyes two. 



The oral organs are represented by a tu- 

 bular rostrum, through the sides of which, 

 from without inwards, two calcareous styles 

 or mandibles pass, and serve to wound the 

 animals forming their prey. At the base 

 of the rostrum is a gizzard with radiating 

 muscular fibres, in Macrobiotus enclosing a 

 kind of framework consisting of six parallel 

 jointed cylinders. 



The alimentary canal is straight, and fur- 

 nished with lateral csecal appendages. The 

 ovary is a simple sac, behind which is 

 situated a seminal vesicle containing sper- 

 matozoa, both opening into a cloaca. But 

 few eggs are produced at a time ; they are 

 either smooth, rugose, or studded with 

 points, and are usually deposited during the 

 ecdysis, the exuviae serving as a protection 

 to them, during the process of hatching. 

 The young resemble the parents. 



The Tardigrada resemble some of the 

 Ptotatoria in reviving after having been kept 

 dried for years. 



Genera : Emydium, Macrobiotics, Milne- 

 sium (Arctiscon, doubtful). 



BIBL. Doyere, Ann. Sc. Nat. 2. xiv. 209, 

 xvii. 103, xviii. 1; Dujardin, x. 185; Vogt, 

 Zool. Brief e, i. 400 ; Kauffmann, Sieb. uud 

 Kott. Zeitschr. iii. 220; Greef, Schultzes 

 Archiv, i. 101 ; Lubbock, Metam. of Insects. 



TARGIO'NIA, Mich. A genus of Pel- 

 liese (Hepaticas), characterized by the almost 

 sessile globose capsule arising from the end 

 of the midrib of the under face of the frond, 

 which is somewhat fleshy, smooth, deep- 

 green, purplish at the edges, and forms large 

 patches on rather moist but exposed banks. 

 The frond has an epidermis on both faces, 

 with stomata and intermediate parenchyma ; 

 the midrib is only apparent beneath, and 

 has radical hairs, with purple scales. The 

 perichaete originates from this rib, on the 

 under surface, rising to the upper side (fig. 

 717). When mature, it is globose, of dark 

 purplish colour and firm texture, and marked 

 with a vertical prominent line or keel : at 

 this line it ultimately splits into two valves 

 (fig. 718). Hofineister's observations, how- 

 ever, show that this envelope grows up 

 after the fertilization of the archegone, 

 which is originally naked in its upper half ; 

 hence it would seem to be a perigone. 

 Several archegones are found half-immersed 

 in the end of the midrib ; and one of these 

 is converted into a fruit ; the lower part be- 

 comes spherical, and the neck forms for a 



