TAPEWORMS. 



49 



(iv) TptmrhijncTius, which ba's four protrusible probosces, also 

 beset with recurved hooks. 



The neck (fig. 14, n). — Here note the first traces of segmenta- 

 tion. At first faint transverse stripes are seen, not extending 

 right across the neck ; farther down they pass from side to side, 

 and small segments are thus marked ofi', becoming larger and 

 more distinct the farther we get from the soolex. The neck 

 is narrow and constricted. 



The proglottides or segments as they become ripe pass out of 

 the host and lead a free life for a short time : they are the 



A 3 



Fig, 12. — Scolex of T.'Enia solium and Proglottis of Tapeworm. 



A, Scolex of Tmnia solium, seen Ironi front. B, Proglottis of Tapeworm, 

 s, Suckers ; h, circle of hooks ; Nc, nerve-cord ; IVv, water-vascular system ; 

 ovary ; T, testes ; Vd, vas deferens ; Vg, vagina ; Ut, uti^rus ; V, vulva ; P, penis. 



reproductive parts, whilst the scolex and neck are the vegeta- 

 tive parts, of the cestode. Yet each segment is practically an 

 individual animal. The internal structure, like the external, is 

 simple ; no alimentary canal will be seen at all ; each segment, 

 which may be oblong or square, broad or narrow, according to 

 the species, is nearly solid throughout. Beneath the outer 

 layer or cuticle is a matrix of small cells, in which glandular 

 cells are seen to be dotted about ; beneath this is a thin layer 

 of longitudinal muscle, then a parenchymatous mass of connec- 

 tive tissue in which small bundles of longitudinal muscle-fibres 

 are scattered, then a layer of circular muscles, and finally in 



D 



