ECHINORHYNCHUS. 



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EELS, 



ECHINORHYN'CHUS, Midler. A ge- 

 nus of Entozoa, order Acanthocephala. 



Char. Body cylindrical or sacciform, 

 somewhat elastic, transversely rugose, ob- 

 tuse at both ends ; furnished with a retrac- 

 tile proboscis, which is armed with from 

 one to sixty regular transverse rows of re- 

 curved spines ; sexes distinct ; no mouth. 



The species, which are very numerous, 

 many microscopic, reside in the alimentary 

 canal, most commonly of fishes and reptiles, 

 less so in that of mammals, and still more 

 rarely in that of birds. 



E. anthuris (PI. 21. fig. 35) is very com- 

 mon in newts ; E. proteus in fish. 



BIBL. Dujardin, Helminth. 483 ; Leuc- 

 kart, Paras. 



ECHI'NUS, Lam. A genus of Echino- 

 dermata, of the family Echinidea. 



The species are popularly known as f sea- 

 urchins,' or ( sea-eggs.' 



The beautifully 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. 



ECTINOSO'MA, Boeck. A genus of 

 Copepodous Entornostraca. 



Four species ; among sea- weeds. (Brady, 

 Copep.) Ray Soc. ii. 8.) 



ECTOCARPACESE. A family of Fu- 

 coidesB. 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. British genera : 



* Frond rigid ; each articulation composed 

 of numerous cells (Sphacelarieae). 



Cladostephus. Ramuli whorled. 

 Sphacelaria. Ramuli distichous, pinna- 

 ted. 



** Frond flaccid ; each articulation com- 

 posed of a single cell. 



Ectocarpus. Frond branching; ramuli 

 scattered. 



Myriotrichia. Frond unbranched; ra- 

 muli whorled, tipped with pellucid fibres. 



BIBL. See the genera. 



ECTOCAR'PUS, Lyngb. A genus of 

 Ectocarpacese (Fucoid Algae), consisting of 

 olive or Drown sea-weeds, with fronds com- 

 posed of flaccid capillary filaments, growing 

 between tide-marks or upon other Algee. 



Fig. 183. 



Filaments of very simple 

 structure, the main axes or 

 branches being composed of 

 single rows of cells (fig. 183), 

 as in Cladophora. The re- 

 productive 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. 

 183) sporanges, and some- 

 times in interstitial cells, be- 

 yond which the branch is 

 prolonged into a fine filament. 

 In E. siliculosus the extremi- 

 ties of the branches are con- 

 verted into sporanges : the Portion of a fl- 

 ceU-contents first divide into g^f ^Jg 

 a number of layers, while the caiTporangS. 1 " 

 part of the filament contain- Magn. 50 diams. 

 ing these swells up and ac- 

 quires the pod-like form; the layers of con- 

 tents are then resolved into lines of zoo- 

 spores 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 zoo- 

 spores. In E. litoralis, Harv., 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 (Har- 

 vey), some of which are common, particu- 

 larly the two above mentioned. 



BIBL. Harvey, Mar. Alg. 58, pi. 9c; 

 Phyc. Brit. pis. 162, 197, &c. ; Eng. Bot. 

 pis. 2290, 2319, &c. ; Thuret, Ann. Sc. Nat. 3 

 ser. xiv. 234, pi. 24. figs. 1-7 ; Agardh, Ann. 

 Sc. Nat. 2 se'r. vi. 197 : Crouan, ibid. xii. 

 p. 248, pi. 5. 



ECTOPLEU'RA, Agassiz. A genus of 

 Hydroid Zoophytes, fam. Tubulariidse. 



E. Dumortierii. Isle of Man, Ostend. 



BIBL. Hincks, Brit. Zooph. 124. 



EEL (Anguilld).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 

 Canada 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 (ANGULLLULA GLUTINIS). 



