52 A FURTHER KNOWLEDGE OF THE CYSTIC CESTODES, 



circular manner, giving rise to a definite sheath (Fig. 3, r. c.) 

 which surrounds the inverted head. This sheath represents the 

 " receptaculum capitis " of Leuckart, concerning which he says,* 

 "The receptacle has least independence in the bladder worms 

 with parenchymatous bodies such as we have seen in Cysticercus 

 (Piestocystis) variabilis and its allies, for there it is not only 

 connected with the mass of the head, but, like the ordinary body 

 muscles, bound up with the tissue of the bladder." Along with 

 the receptacle, mention must be made of the numerous muscular 

 or elastic fibres which run through the body tissue. They are 

 composed of a homogeneous substance which stains uniformly and 

 shows no trace of cellular structure. In Fig. 3 in the receptacle 

 they are seen to be more or less radially arranged, while in Fig. 2 

 some of the fibres are seen to take a longitudinal course, passing 

 forwards like the similar fibres in the Lialis Cysticercus, to be 

 inserted into the head. 



The bladder cavity in this form is represented by an irregular 

 cavity occupying the centre of what represents the caudal bladder 

 of ordinary Cysticerci, and not distinctly marked off from the 

 surrounding ground tissue. The cavity is filled by a granular 

 material consisting of a homogeneous matrix with granules which 

 stain deeply with cochineal, and which represent the products of 

 degeneration of the original central tissue, which in the Cysti- 

 cercus from Lialis {seq.) persists unaltered. 



Frontal sucker. — The frontal sucker is situated mediaiily in the 

 inner part of the invaginated head, in what will in the evaginated 

 condition be its apex. In sections (Figs. 2 and 4), both by its 

 structure and staining properties, it can readily be distinguished 

 from the surrounding tissue. At its narrower anterior end is a 

 slit-like aperture whicli places the cavity of the sucker in commu- 

 nication with the cavity of invagination of the head. The sucker 

 cavity (Fig. 4, s. c.) is much wider than its opening, but is very 

 shallow, so shallow, indeed, that the aperture and the cavity only 



* " Parasites of Man," English Edition, p. 347. 



