ECTOCARPACEiE. 



[ 220 ] 



EGGS. 



The species are popularly known as * sea- 

 urchins/ or * sea-eggs.' 



The beautifull}^ symmetrical structure of 

 their spines, and their curious Pedicellarice, 

 afford favourite objects to the admirers of 

 nature's minute wonders. These organs are 

 not confined to this single genus of the 

 family. 



See EcHiNODERMATA and Shell. 



BiBL. Forbes, Brit. Starfishes, Sfc.y p. 167; 

 Agassiz, Monogr. d'Echinoderm. 



ECTOCARPACEiE.— A family of Fu- 

 coidese. Olive-coloured, articulated, fili- 

 form sea-weeds, with sporanges producing 

 ciliated zoospores either external, attached 

 to the jointed ramuli, or formed out of some 

 of the interstitial cells. 



Synopsis of the British Genera. 



* Frond rigid j each articulation composed 

 of numerous cells (Sphacelariese). 



I. Cladostephus. Ramuli whorled. 



II. Sphacelaria. Ramuli distichous, 

 pinnated. 



** Frond flaccid J each articulation com- 

 jjosed of a single celt. 



III. Ectocarpus. ' Frond branching, ra- 

 muli scattered. 



IV. Myriotrichia, Frond unbranched, 

 ramuli whorled, tipped with pellucid fibres. 



BiBL. See the genera. 



ECTOCARPUS, Lyngb.— A genus of Ec- 

 tocarpacese (Fucoid Algse), consisting of 

 olive or brown sea-weeds, with fronds com- 

 posed of flaccid capillary filaments, growing 

 between tide-marks, or upon other Algae. 

 The filaments are of very simple structure, 

 the main axes or branches being composed 

 of single rows of cells (fig. 186) Ym. 186. 

 as in Cladophora. The repro- 

 ductive bodies at present 

 known, ciliated zoospores, are 

 formed in the cells of the 

 branches; sometimes in the 

 terminal cells, producing the 

 siliquose or elliptical (fig. 186) 

 sporanges, and sometimes in 

 interstitial cells, beyond which 

 the branch is prolonged into 

 a fine filament. In E. si- 

 liculosus the extremities of 

 the branches are converted 

 into sporanges ; the cell-con- 

 tents first divide into a number Portion of a fila- 

 of layers, while the part of ment bearinp: la- 

 the filament containing these terai elliptical spo- 

 swells up and acquires the Magn. 50 diams. 



Ectocarpus 

 verminosus. 



pod-like form; the layers of contents are 

 then resolved into lines of zoospores 

 piled regularly one above another. The 

 summit of the pod finally bursts, and the 

 zoospores escape. The empty sporange 

 exhibits fine transverse striae, as if delicate 

 septa existed between the layers of zoospores. 

 In E. litoralis, Harv. {E. firmus, Ag.) the 

 fertile cells are not terminal, but interstitial, 

 and form beaded rows surmounted by a hair- 

 like prolongation of the branch; the zoo- 

 spores escape by a lateral pore. The germi- 

 nation of these zoospores has been observed 

 by Thuret. Sixteen British species are de- 

 scribed by Harvey, some of which are com- 

 mon, particularly the two above mentioned. 



BiBL. Harvey, Brit. Mar. Alg. 68. pi. 9c; 

 Phyc. Brit. pi. 162. 197, &c. ; English Bo- 

 tany, pi. 2290. 2.319, &c.; Thuret, Jnn. des 

 Sc. nat. 3 ser. xiv. p. 234. pi. 24. figs. 1-7 ; 

 Agardh, Ann. des Sc. nat. 2 ser. vi. p. 197 ; 

 Crouan, ibid. xii. p. 248. pi. 5. 



EEL {Anguilla). — It is popularly believed 

 that the eel has no scales. They are, how- 

 ever, present, but immersed in the skin ; and 

 their structure is curious (Scales of Fish). 

 The dried skin of the Eel, mounted in Ca- 

 nada balsam, exhibits well the scales, covered 

 by the epidermis, and the beautiful layer of 

 stellate pigment-cells. 



BiBL. Yarrell, Brit. Fishes, ii. 



EELS, in paste (Anguillula gluti- 



NIS). 



EELS, in vinegar (Anguillula aceti). 



EGGS. — The minute ova of certain animals 

 have always been favourite microscopic objects 

 on account of their curious forms, the beau- 

 tiful structure of their outer chitinous enve- 

 lope, their varied colours, and the singular 

 lids with which some of them are furnished. 

 The most interesting are those of insects; 

 among them we may mention the brown 

 eggs of the puss-moth, Cerura vinula (PL 31. 

 fig. 19); of the large cabbage-butterfly, Pon- 

 tiahrassicce (PI. 31. fig. 32), or the small 

 cabbage-butterfly, Pontia rajjce (PL 31. fig, 

 21); of the small tortoise-shell butterfly, Fa- 

 nessa urticce ; the angle-shades moth, Noctua 

 or Phlogophora meticulosa ; the common 

 meadow brown butterfly, Hipparchia Janira; 

 the brimstone-moth, Rumia Cratocgata ; the 

 water-scorpion, Nepa ranotra; the common 

 cow-dung-fly, Scatophaga stercoraria ; the 

 bug, Cimex lectularius (PL 31. fig. 20), &c. 



Their surfaces exhibit markings of the 

 most varied forms; spines, tubercles, pits or 

 processes, sometimes of considerable length 

 (PL 16. figs. 22, 23), often arranged with 



