YEW. 



[ 825 ] 



ZOOSPORES. 



Desni., which agrees with Cryptococcm ffhi- 

 fi/iis, Kiitz. ; the globular form in the Vine- 

 gar-plant is Kiitzing's Ulvina aceti; the 

 tilamontous form with simple moniliform 

 fruit (fig. 7oG) is Tontln cerevisice, Turpin ; 

 without fruit, species of Hygrocroch or Lep- 

 tomitus, tlie final form being apparently 

 PeniciUhnn r/laiicitm (PI. 26. fig. 15). 



The Yeast-plant is truly most ubiquitous ; 

 but so are the conditions for its growth, 

 while its reproductive power is enormous, 

 and its small size renders it liable to be 

 scattered by imperceptible movements of 

 the air. Asperffilli(s (/laucus is almost as 

 constant in its' favourite nidus, cheese ; 

 Mticor mucedo on paste, &c. ; Botrytis vul- 

 yaris on dead leaves and stems in damp 

 places, iSrc. : and all these are certainly not 

 pseudomorphic productions ; and if, as we 

 believe really to be the case, yeast is but 

 the conidial form of PenicUUuin glmmnn, 

 there has been no lack of the spores of the 

 latter in the air, in any situation where we 

 have ever exposed vegetable substances for 

 any length of time to a damp atmosphere. 



i^ees has lately observed in yeast, which 

 he calls Saccharomyces, that when sown on 

 plaster of Paris, or some convenient sub- 

 stance, certain cells at length swell and 

 contain sporidia. But after the fact that 

 sporidia are developed within the threads 

 of Chionyphe and in Hemileia, this does not 

 seem of much consequence. 



The Yeast-fungus is often developed in 

 ripe grapes, causing -vinous fermentation. 

 In an article published in Aim. d. Sc. Nat. 

 the globules are regarded by Karsten as 

 merely pathological; but this is contradicted 

 by the facts above mentioned. 



' BiBL. Turpin, Mem. de VInstitut, xvii. 

 93; Lowe, Tr. Edinh. Bot. Soc. 1857; 

 Bail, Flora, 1857, 417; Berkeley, Crypt. 

 Bot. 242, 299 ; Karsten, Ann. N. H. 4. xiii. 

 161 ; Rees, AlkohoIydhrimyspiJze, 1870 ; 

 Sachs, Bot. 254; and the BM. of Fermen- 

 tation. 



YEW. See Taxtjs. 



ZA'MIA, Liudl. See CYCADACEiE. 



ZAN'CLEA, Gegenbaur. — A genus of 

 Corynidse, Hydroid Zoophytes. 



Char. Stem simple or branched, rooted 

 by a creeping filiform stolon ; polypes more 

 or less clavate. Tentacles capitate, scat- 

 tered over the body ; gonophores borne on 

 the body of the polype and producing free 

 medusiform gemmae. 



-The larval stage of some of the 



Z. imple.ra, marine, on shells, stones, &c. 



BiBL. Gegenbaur, Versvch eines Syst. d. 

 Medusen, Zeit. f. wiss. Zool. 1856,' 229; 

 Hincks, ITyd. Zooph. 58. 



ZAUS, Goodsir. — A genus of Copepodous 

 Entomostraca. Two species, marine. (Brady, 

 Cope p. ii. 153.) 



ZETES, Koch.— A genus of Arachnida, 

 of the order Acarina and family Oribatea. 

 It is consolidated with Galumna. 



ZINC— The crystals of the lactate, as 

 deposited from an aqueous solution, are re- 

 presented in PL 11. fig. 20; they belong to 

 the right-rhombic prismatic system. 



The chloride of zinc is useful as a preser- 

 vative of animal tissues. (See Preseeva- 



TION.) 



Chtm-iodide of zinc. See Schulze's Test. 



BiBL. That of Chemistry. 



ZOEA.- 

 higher Crustacea. 



ZONARIA, Harvey (Aylaozom'a, Zanard, 

 Kiitz.). — A genus of Dictyotacese (Fucoid 

 Algse), of which the British species, Z. par- 

 vula, forms olive-green, membranous, fan- 

 shaped fronds, 1" or more in diameter, 

 growing over stones or corallines, to which 

 it attaches itself by whitish fibres on the 

 lower surface. It is scarcely marked with 

 concentric lines like Padina. The fructifi- 

 cation occurs in scattered sori on both sur- 

 faces, and is apparently analogous to that of 

 Padina, but requires further examination, 

 since Thuret has shown that the true Dicty- 

 otaceae have peculiar reproductive organs, 

 spores, tetraspores, and antheridia, so that 

 they stand between the Fucacete and the 

 Florideee. 



BiBL. Harvey, 3far. Aly. 38, pi. 6 D; 

 Thuret, Ann. Sc. Nat. 4. iii. 25. 



ZONOTRIC'HIA, Ag.=AiNACTis and 

 Euactis. (Rabenht. Aly. ii. 212.) 



ZOOGLCEA, Cohn. See Bacterium. 



ZO'OID. — The more or less completely 

 independent organisms, produced by gem- 

 mation or fission, whether these remain at- 

 tached, or are liberated and set free. (Ni- 

 cholson, Zool.) 



ZO'OPHYTES, or Ccelenterata. See 

 Animal Kinc4Dom, and Polypi ; also 

 Hamann, Organism. Hydroidpolypen, 1882, 



ZO'OSPORES.— The name given to the 

 ciliated active gemmoe orGoNiDiA produced 

 either singly or, more frequently, after 

 segmentation, in numbers, out of the con- 

 tents of oi'dinary or special cells of the Algae, 

 without any previous process of fertilization. 

 These bodies are generally discharged from 



