TAPEWORM FROM APTEEYX. 85 



serve for the better dispersion of the ripe eggs contained 

 within. The camera drawings (figs. 6 and 7) show the posi- 

 tion of these eggs in the terminal and in the isolated pro- 

 glottids. The spacious uterus occupies the anterior region 

 of the proglottid. After separation (or even before) the 

 circular muscles of the hinder margin contract more strongly 

 than elsewhere, so that this border is thrown into a curve ; 

 the anterior margin is thus spread out, and by contraction 

 of the longitudinal muscles the body-wall is drawn away 

 from the uterus, and during this process the thin walls of the 

 latter become ruptured, and thus the eggs are dispersed. 

 This seems to render improbable any prolonged independent 

 life of the proglottid (such as is recorded for those of Da v. 

 proglottina). The ripe eggs measure '03 mm. in diameter 

 over all, and possess two coats, an outer granular cellular 

 envelope, and an inner, firmer, thinner one, pressed against 

 which there appear to be flat nuclei (fig. 8) . 



The scolex, which is very much flattened from side to side, 

 is provided with the usual four suckers or acetabula hollowed 

 in the sides, and corresponding to the flat faces of the strobila 

 (fig. 4). Each acetabulum presents the characters usual in 

 the family Tseniadae, but is rather oval than circular in 

 outline, and seems remarkable for the fact that its lower 

 posterior margin projects upwards and outwards as a kind of 

 flap, so that sometimes in mounted specimens, as well as in 

 unmounted ones, examined under spirit, the aperture appears 

 reduced, and may even be triangular in form ("figs. 2 and 3). 

 From the various conditions here figured it seems certain 

 that this '' flap " is moveable, the general effect being that 

 the aperture faces forwards instead of outwards. 



The apex of the scolex is provided with an armed rostellum, 

 which bears a ring of eighteen or twenty small booklets 

 arranged really in two circlets, but very close to one another, 

 so that the line of bases forms a zigzag (see figs. 5, 16, and 

 17), each of which is provided with a "handle" nearly as 

 long as the " blade," while the "guard" is short but quite 

 distinct. The entire length of this booklet is -04 mm. In 



