ECCRIXA. 



[ 273 ] 



ECHINOCOCCUS 



has no aperture ; the food, consisting of the 

 juices of the prey, passes throuj^h a canal 

 ti-aversing the long, siciile-shaped, acute 

 mandibles (c). Maxillae (d) slender, cy- 

 lindrical, and termiuated by a short lateral 

 spine ; tht» maxillary palpi (e) are of the 

 same thickness, arising from the tip of the 

 maxilL^e, and seven-jointed. Labial palpi 

 (/■) slender and four-jointed, the fii'st and 

 third joints being very short. 



The head of the larva, and the three pairs 

 of legs of the perfect insect, are commonly 

 mounted as microscopic objects, as are 

 those of other genera belonging to the fa- 

 mily — Acilius &c. 



BiBL. "Westwood, Introd. &c. i. p. 95 ; 

 Stephens, Brit. Beetles. 



E. 



ECCRI'NA, Leidy. — See Enterobrt- 

 us. 



EOHINEL'LA, Acharius. — A term ap- 

 plied first to a group of ova of some aquatic 

 animal, next to a genus of Infusoria, more 

 recently to a genus of Diatomaceee, but now 

 no lonsrer used. 



ECHINOBO'TRYUM,Corda.— A doubt- 

 ful genus of Torulacei (Coniomycetous Fun- 

 gi). JE. atrum has been found in Britain, 

 parasitic upon a species of PacJmocybe. 



BiBL. Berk, and Broome, Ann. N. H. 

 2 ser. V. 460 ; Corda, Icon. Fung. ii. fig. 6. 



ECHINOCOCCUS, End.— A supposed 

 genus of Entozoa, of the order Cestoidea 

 and family Cystica ; now shown to consist 

 of the larvae of T^nia. 



Char. Consisting of a vesicle of very va- 

 riable size, sometimes surrounded by a coat 

 of condensed areolar tissue, and containing 

 within, one or more secondary cysts ; at- 

 tached to the walls of these cysts, or sus- 

 pended in their liquid contents, are nume- 

 rous oblong, rounded, or oval bodies (sco- 

 lices), each with four suckers, and a double 

 crown of hooks. 



E. veterinoriim, the larva of Taenia echi- 

 nococcus (PI. 21. figs. 1 & 2), occurs in the 

 liver, the cavity of the abdomen, the heart, 

 the voluntary muscles, and the ventricles 

 of the brain of man ; in the liver, lungs, &c. 

 of the ox, sheep, goat, ape, pig, &c. Com- 

 monly called hydatids. The walls of the 

 brood-cysts consist of numerous concentric 

 layers or plates, resembling those of colloid 

 cells or cysts. The liquid existing within 



the cysts is yellowish or reddish, albumi- 

 nous, and frequently contains plates of cho- 

 lesterine, and crystals of bilifulvine (PI. 13 

 fig. 15) (see Bile) ; some of the latter re- 

 semble in form and colour those of Hjema- 

 TOIDINE. The scolices appear to the naked 

 eye as minute, white, opaque si^ecks, varying 

 in size from about the 1-300 to 1-100" in 

 length. They also vary greatly in form ; 

 when the head is retracted (fig. 1 a) they 

 appear more rounded than when this is 

 protruded (fig. 1 c, 1 d, If). The hooks 

 surrounding the anterior end of the body 

 (fig. 1 b) consist of a broadish basal portion, 

 an internal transverse blunt tooth, and a 

 carved terminal portion or claw ; they are 

 about the 1-1500 to 1-1000" in length. In 

 some of the scolices a kind of pedicle exists 

 at the base, by which they are attached to 

 the wall of the cyst (figs. 1 a and 1 c) ; some- 

 times two or more lines may be perceived, 

 running from the head towards the pedicle, 

 and connected in front by a transverse line 

 — probably representing vessels (fig. 1 c). 

 Interspersed through the substance of the 

 body are minute highly refractive corpus- 

 cles, containing carbonate of lime. 



In the quite recent state, the scolices 

 have been seen swimming actively in the 

 liquid of the cyst ; this motion is produced 

 by cilia existing upon the surface of the 

 body. Mingled with the perfect scolices 

 are generally found some in which neither 

 hooks nor suckers are visible, and in which 

 the form is very irregular ; some of these 

 assume the natui'al form when treated with 

 acetic acid. 



The scolices appear usually to be deve- 

 loped by gemmation from the interior of 

 the cysts; but, as Kuhn long since showed, 

 they are sometimes produced by external 

 gemmation (fig. 2) : the contents produce 

 a slight protrusion of a part of the wall of 

 the cyst; the protruded portion enlarges, 

 afterwards becoming constricted at its base, 

 at last probably separating from the parent, 

 to become itself a parent in the same man- 

 ner. The example figured in PI. 21. fig. 2 

 was not isolated ; there were many, con- 

 tained with numerous other larger cysts, of 

 the most varied sizes, all in one very large 

 parent cyst. 



The Echinococci do not attain their full 

 development into Tcenice, unless they reach 

 the alimentary canal. The cysts and their 

 contents, including the Echinococci, some- 

 times undergo a kind of degeneration, be- 



