ENDOSPERM. 



[ 229 ] 



ENTOMOSTRACA. 



other, are separated merely by a porous dia- 

 phragm or an organic membrane. A diffusion 

 takes place, by which the liquids become 

 mixed, but one of them flows more rapidly 

 into the other. Thus when alcohol and water 

 are so placed, the water flows into the alcohol 

 (endosmose} much more strongly than the al- 

 cohol into the water (exosmose). The same 

 attraction occurs when syrup or a solution of 

 gum is substituted for the spirit, and also al- 

 kaline salts. When acids or acid salts are 

 placed in the same relation to water, the 

 current is strongest towards the water. Acids 

 and alkaline solutions exert the strongest 

 action, neutral substances the weakest. Di- 

 lute solutions act more efficiently (propor- 

 tionately) than strong ones. The phenomena 

 have been attributed to diffusion and to ca- 

 pillarity, but these are insufficient to explain 

 them. Graham thinks the osmotic movements 

 attributable to chemical action. The import- 

 ance of the effects of endosmose on micro- 

 scopic objects viewed in liquids, has been 

 mentioned in the INTRODUCTION (xxxv). 

 Delicate structures are often advantageously 

 wetted with dilute solutions of sugar, or bet- 

 ter, common salt, to prevent the changes 

 from endosmosis, which result from the use 

 of pure water. 



BIBL. Fischer, Poggend. Annal. Bd. xi. 

 p. 126 ; Dutrochet, Cycl Anat. and Phys. 

 ii. p. 98; General Works on Physics, as Buff, 

 Experimental-Physik ; Pouillet, Siemens de 

 Physique; PescheVs Physics, &c.; Graham, 

 Proc. Royal Soc. vii. p. 83. 



ENDOSPERM. See ALBUMEN, of Plants. 



ENDOSPORE. The name applied by 

 some authors to the inner coat of spores. 

 See SPORE. 



ENERTHENEMA, Bowm. A genus of 

 Myxogastres (Gasteromycetous Fungi), in- 

 teresting from the fact that the spores have 

 been observed in situ; they are produced, 

 five or six together, in globular sacs (asci) 

 attached to the free apices of the filaments 

 of the capillitium, which arise from a disk at 

 the top of the percurrent stem. E. elegans 

 was found by Mr. Bowman near Wrexham, 

 and it has since been found in South Carolina. 



BIBL. Bowman, Linn. Trans, xvi, p. 151. 

 pi. 16; Berk, and Broome, Ann. Nat. Hist. 

 2 ser. v. p. 366. pi. 11. fig. 7- 



ENTEROBRYUS, Leidy. A supposed 

 genus of Kiitzing's Leptomiteae, probably 

 the mycelium of some fungus, found in the 

 intestines of insects. 



ECCRINA, Leidy, is another of these forms. 



BIBL. Leidy, Proc. Nat. Hist. Soc. Phi- 



ladelphia, 1849. p. 225, Ann. Nat. Hist. 

 2 ser. v. p. 72 ; Robin, Vegetaux Parasites, 

 ed. 2. 1853. p. 395. pi. 4. figs. 5, 6. 



ENTEROMORPHA, Link. A genus of 

 Ulvacese (Confervoid Algae), consisting of 

 aquatic and marine plants, with branched, 

 tubular, green fronds, the walls of the tubes 

 being composed of a single flat layer of poly- 

 gonal cells. These plants are reproduced by 

 ciliated zoospores, formed in considerable 

 numbers from the transformed contents of 

 the cells (PL 5. fig. 4). In this genus Thu- 

 ret states that two forms of zoospores occur; 

 one large and four- ciliated, the other in 

 fronds with a yellower tint, smaller, and 

 with two cilia ; both kinds germinate. The 

 zoospores escape from the cells by a pore on 

 the outer surface (PI. 5. fig. 4 a), near the 

 centre of the cells, and the latter persist for 

 some time in an empty condition. The 

 marine forms, of which nine species are 

 described by Harvey, are mostly from 1-2'" 

 to several lines in diameter, but many inches 

 long. E. Grevillei, Thuret ( Ulva Lactuca, 

 Grev., Harv.), however, is thicker and sac- 

 cate, finally bursting. E. intestinalis, which 

 grows both in the sea and in brackish and 

 freshwater ditches, often attains a length of 

 2 feet and more, and varies in thickness from 

 1"' to 2-3''. 



BIBL. Harvey, Brit. Mar. Ala. p. 213. 

 pi. 25 D, Phyc. Brit. pi. 63. 262. 282, &c. ; 

 Greville, Alg. Brit. p. 179-82, Sc. Crypt. Fl. 

 t. 313, Eng.Bot. 2137 & 2328 ; Thuret, Ann. 

 des Sc. nat. 3 ser. xiv. 224. pi. 20. fig. 8-12; 

 Mem. Soc. desSc. nat. de Cherbourg ,ii. (1854). 



ENTEROPLEA, Ehr. A genus of Rota- 

 toria, of the family Hydatinaea. 



Char. Eye-spots none; teeth absent; foot 

 forked. 



E. hydatina (PL 34. fig. 27). Body conical, 

 hyaline; foot small; aquatic; length 1-120". 



Resembles Hydatina senta, but is smaller. 



BIBL. Ehrenb. Infus. p. 411. 



ENTOMONEIS, Ehr. = Amphiprora, in 

 part. E. alata = A. alata. 



ENTOMOSTRACA. A division of the 

 class Crustacea. 



Char. Free; aquatic or marine; body 

 more or less distinctly jointed, mostly con- 

 tained in a horny, leathery or brittle shell or 

 carapace, formed of one or more pieces, 

 sometimes bivalve; branchiae attached either 

 to the jaws or legs ; legs jointed, and more 

 or less ciliated ; development accompanied 

 by a regular moulting or change of shell, 

 sometimes amounting to metamorphosis. 



Many of the Entomostraca are very com- 



