590 



DESCRIPTION OF THE ADULT T^IXIA ECHIXOCOCCUS. 



sist of spermatozoa, in other words, into a receptaculum seminis. 



Opposite the opening of the vagina there rises from this recep- 

 taculum a fertilising canal of 

 appreciable width, and distin- 

 guished by the double contour of 

 its walls. After a short course, 

 this divides into two narrower 

 ducts, of which the one bends for- 

 wards, while the other continues 

 the original course backwards. 

 The former of these two canals is 

 the oviduct whose upper end is 

 connected as usual with the two 

 ovaries. l The csecal tubules which 

 form the glands are short and 

 wide, and so slightly separated 

 that the ovaries look more like 

 lobulated sacs than aciniform 

 glands. Internally, the eggs may 

 be recognised as sharply defined 

 balls about 0*01 mm. in size. 

 The second canal divides further 

 down into two ducts one of 

 which enters the simple sacular 







Flo. 318. Generative organs of Tcenia 

 tohinococcus. Male organs t.t., testea ; 

 c.p. , cirrhus-pouch ; c., cirrhus, curving round 

 to enter the vagina. Female organs ov., 

 ovary ; o.d. y oviduct ; r.., receptaculum 

 seminis ; y.j/., yolk-gland ; ut.. tube, pro- 

 bably leading to the uterus ; f.c., fertilising 

 canal ; v., vagina. ( x 80.) 



yolk-gland, while the other is probably in connection with the uterus. 

 The latter appears from the first as a wide cavity. It is some- 

 what late before it is distinguishable, namely, after the ovaries 

 have liberated their contents, and, like the yolk-glands, have 

 disappeared. I have not been able to find a shell-gland in Tcenia 

 echinococcus. 



Situation and Habits. This worm usually occurs in considerable 

 numbers, sometimes in many thousands, between the villi of the small 

 intestine, so that only the milk-white ripe proglottides project. 

 When the latter are not present, the worms can hardly be recognised 

 with the naked eye. 



In the still warm intestine they exhibit lively and striking move- 

 ments. They elongate and shorten their joints, especially the first, 

 and move forwards in the surrounding intestinal mucus quickly and 

 powerfully, almost like leeches. Sometimes the body becomes so 

 thin that they almost resemble Kematodes. 



1 The narrowness and general nature of the transverse efferent ducts of the ovaries 

 exclude the possibility (maintained by Sommer in regard to the other cystic tape- worms, 

 see p. 444) that they are glandular lobes. 



