212 ON THE ANATOMY OF THE ECHINOCOCCUS VETERINORUM 



vesicle we see little vesicles attached here and there, which contain a 

 finely granular substance ; out of this mass the Echinococci proceed 

 (hervorkeimen), sometimes only one, sometimes two, six, seven, or 

 more. A portion of the granular mass becomes, in fact, sharply 

 marked off, forms a small roundish body, which, however, by one 

 of its ends, still clearly passes into the rest of the substance ; the 

 rounded body gradually takes on a pea shape, the constricted portion 

 elongates, and the body which has now assumed a more oval form, 

 is connected only by a delicate viscid thread with the mass from 

 which it sprang ; we soon now observe in the interior of the body the 

 circlet of hooks and the glassy corpuscles. The Echinococcns-\iea.d 

 thus far developed now begins to move — everting and retracting 

 its suckers and hooks ; the whole body being at the same time some- 

 times elongated, sometimes contracted. The development of the 

 Echinococci having proceeded to this stage, the delicate membrane 

 in which they are enclosed bursts. The young Echinococci do not 

 immediately fall out, for they are all connected to the inner surface of 

 the membrane, which until now has enclosed them, by means of 

 a delicate cord or process of the latter, which penetrates at the 

 posterior extremity of the Echinococcns, through a pit, into the interior 

 of the body of the Echinococcns. The pit looks almost like a sphincter, 

 holding just that cord of the membrane ; only after an interval do 

 the cords and the bodies of the Echinococci become separated. The 

 mode of connection of these cords with the bodies of the Echinococci, 

 and their separation from them, reminds one completely of the relation 

 which the bodies and tails of the Cercarice have to one another. The 

 membranous covering of the young Ecliinococci wrinkles up immedi- 

 ately when it is torn. The Echinococci become everted, and so form a 

 rounded heap, in the middle of which the collapsed investment lies 

 hidden, the Echinococci being attached to it like the polypes upon a 

 polypidom. 



" Such masses of Ecliinococci either remain for a long time hang- 

 ing to the inner surface of the parent vesicle, or they become de- 

 tached from it before the single Ecliinococci have separated from the 

 wrinkled membrane. The granular mass contained in the vesicles is 

 probably comparable with nothing else than with a yelk mass, which 

 supplies the heads with the substance necessary for their develop- 

 ment through those fine cords. For the rest, I will not undertake 

 to decide whether all those larger and smaller vesicles, which con- 

 tain Echittococcus-hea.d?, and float about free among fully-developed 

 Echinococcus-heSids in the cavity of the parent vesicle, are de- 

 tached from the wall of the latter, or whether some few of them 



