TYNDARIDEA. 



[ 659 ] 



ULVA. 



bearing minute corpuscles (spermatia), which 

 when mature escape from the pore in a ten- 

 dril (as in Cytispora] if moistened or pressed 

 (see also CENANGIUM). 



BIBL. Berk. Brit. Flor. ii. pt. 2. p. 210, 

 Ann. Nat. Hist. 2nd ser. vii. p. 185, Hook. 

 Journ. of Botany, iii. p. 322 (1851); Tulasne, 

 Ann. des Sc. nat. 3 ser. xx. p. 143. pi. 16. 

 figs. 15, 16; Fries, Summa Veg. p. 399 ; 

 Greville, Sc. Crypt. Fl. pi. 335. 



TYNDARIDEA, Bory. See ZYGNEMA. 



TYPHLINA, Ehr. An imperfectly exa- 

 mined genus of Rotatoria, of the family 

 Philodinaea. 



T. viridis (PL 35. fig. 33). Found in 

 Egypt. 



BIBL. Ehrenberg, Infus. 483. 



U. 



ULOTHRIX. A genus of Confervoid 

 Algae, perhaps referable to the Chaetophora- 

 ceae, allied to Draparnaldia and Stigeoclo- 

 nium. They consist of unbranched filaments 

 adhering loosely together to form a mucous 

 stratum, growing upon stones, &c. in fresh 

 water. The filaments are composed of short 

 hyaline cells (PI. 5. fig. 6), the green con- 

 tents of which are at first granular, adhering 

 to the walls (a), then contracted into trans- 

 verse bands (b), and finally converted into 

 two, four, or more zoospores, with four cilia 

 (c). Hassall appears to have confused these 

 plants with the Oscillatoriaceous genus 

 Lyngbya ; his L. muralis is apparently the 

 true plant, his L. copulata perhaps a Schizo- 

 gonium ; the rest of his species belong here, 

 since, according to Kiitzing, Berkeley's 

 Sphceroplea crispa and punctalis belong to 

 this genus. There appear to be several 

 British species, but we give them with some 

 doubt. 



1. U. zonata. Filaments 1-960" in dia- 

 meter, joints about as long (Lyngbya zonata, 

 Hass. pi. 59. figs. 2, 3, 6). 



2. U. pectinalis. Filaments 1-1800, 

 1-1200, 1-960" in diameter, joints one- 

 half or one-fourth the length ; fertile cells 

 swollen (L. zonata, Hass. pi. 60. figs. 1, 

 4,5). 



3. U. crispa. Filaments very long, 1-600" 

 in diameter, joints one-half or one-third as 

 long (Cow/, bicolor, Eng. Bot. p. 2288). 



4. U. floccosa. Filaments 1-2160 to 

 1-1800" in diameter, joints about as long 

 (Lyngb. floccosa, Hass. pi. 60. figs. 1 & 2). 



5. U. punctalis. Filaments 1-3000 to 

 1-2500" in diameter, regularly torulose; 



joints two and a half times as long as broad 

 (Lyngb. punctalis, Hass. pi. 60. fig. 4; L. 

 virescens, fig. 3, and L. vermicularis, Hass. 

 fig. 5, are scarcely distinct from this). 



6. U.speciosa. Filaments 1-780 to 1-420" 

 in diameter, curled ; sterile joints one-half 

 or one-third as long. 



BIBL. Kiitzing, Sp. Alg. p. 345, Tab. 

 Phyc.ii.-, Hassall, Brit. Fr. Alg. p. 219; 

 Thuret, Ann. des Sc. nat. 3 ser. xiv. p. 222. 

 pi. 18. 



ULVA, Linn. A genus of Ulvacese (Con- 

 fervoid Algae), here taken in the sense of 

 Thuret. The plants are all marine, consist- 

 ing of broad, green, simple or lobed, mem- 

 branous fronds, growing upon rocks and 

 stones. They are distinguished from Mono- 

 stroma by being composed of a double plate 

 of cellular tissue, and from Enteromorpha 

 by the two plates being permanently adhe- 

 rent, and not separating so as to convert the 

 flat plate into a sac. The cells are round- 

 ed-angular (PI. 5. figs. 2 & 3), and are at 

 first filled with amorphous green colouring 

 matter, which subsequently becomes collected 

 into masses (a), ultimately converted into 

 numerous zoospores. Under the influence 

 of light, these soon " swarm" and break out 

 from the cells by a pore in the outer wall 

 (fig. 3 b}. The emptied cells give a pale co- 

 lour to the parts of the frond where they 

 are situated. The zoospores appear in two 

 forms, some large and bearing four cilia (fig. 

 3 c), others much smaller, and possessed of 

 only two cilia (fig. 2 b). The fronds in which 

 the latter occur are generally of a yellower 

 colour. Thuret has seen both kinds germi- 

 nate. As defined by that author, the British 

 species stand as follows : 



1. U. Lactuca, L. Frond broadly ovate 

 or oblong, 6 to 18" long, and several inches 

 wide (Engl. Bot. pi. 1551; U. latissima, 

 Harvey and Greville ; Phycoseris gigantea, 

 Kiitz.). 



/3. latissima. Frond 3' or more long, 18" 

 or more wide ; found in the muddy water at 

 the entrance of harbours (Phycoseris Myrio- 

 trema, Kiitz. Sp. Alg.}. 



2. U. Lima, L. Frond linear-lanceolate, 

 6 to 24" long, 1-2 to 3-2" wide. (17. Lac- 

 tuca, Greville, Sc. Crypt. Fl. pi. 313 ; Har- 

 vey, Phyc. Brit. pi. 243 = Enteromorpha 

 Grevillei, Thuret, olim). 



BIBL. Harvey, Brit. Mar. Alg. p. 216. 

 pi. 25 B ; Thuret, Mem. de la Soc. de Cher- 

 bourg, ii. (1854), Ann. des Sc. nat. 3 ser. xiv. 

 p. 224. pi. 20; Greville, Harvey, Kiitzing, 

 I. cit. supra. 



2u2 



