TiENIA SOLIUM. 



213 



dependent on age nor situation. They are equally present and 

 abundant in tlie pork-measle, and in the specimens of Gysticer- 

 cus cellulosce derived from the human subject. The cephalic hooks 

 of this cestode are comparatively large, those of the greater series 

 measuring as much as jjo', whilst the smaller have an extreme length 

 of about 220 '. The sharp thorn-hke extremities of the hooks of 

 both circles terminate outwardly at a common point of distance 

 from the centre of the rostellum ; so that a line carried from point 

 to point, in succession, will indicate the circumferential limit of the 

 double crown, forming, in fact, a simple circle. The roots and 



Fig. 46. Fragment of the strobile of Tcenia solium, Linneus ; showing, more particularly, the 



reproductive apparatus and water ressels of a single proglottis. — Bokitansky. 



stems of the hooks are received into a corresponding double series 

 of socket-like pouches, which are visible even when the hooks them- 

 selves may be wanting. They were, I beheve, first accurately de- 

 scribed by Kiichenmeister. The tegumentary covering of the head 

 differs in no important particular from that of the rest of the body, 

 displaying an external thin, smooth, transparent, chitinous epidermis 

 superimposed on a rather thick, fibrous corium. Beneath the 



