BY J. P. HILL. 83 



Fig. 4. — Portion of a transverse section (slightly oblique) of a Cysticercus 

 with invaginated head, passing through frontal sucker. Chrom- 

 osniic acid and Ehrlich's Hcematoxylin. Zeiss. C. and oc. 1, 

 cam. luc. /. s., frontal sucker; c. s., cavity of sucker; c. /., 

 circular fibres ; r./., radial fibres ; I. s., lateral sucker. 



Fig. 5.— Outer portion of a transverse section of a Cysticercus about its 

 middle region. Corrosive sublimate and Ehrlich's Hsematoxylin, 

 Zeiss. D., oc. 1, cam. luc. ; details with Zeiss. F. c, cuticle; 

 c. /. and l.f., circular and longitudinal fibres of dermo-elastic 

 layer; s. c, subcuticula ; r. c. c, cavity with remains of cal- 

 careous corpuscle ; g. t. c. , cells of ground tissue ; m, matrix ; 

 e./., elastic fibres. 



Fig. 6. — Outer portion of a longitudinal section. Corrosive sublimate and 

 cochineal. Zeiss, F., oc. 1, cam. luc. c' c", outer and inner 

 layers of cuticle ; c. n. c, cavities containing a number of small 

 calcareous corpuscles. 



Plate iv. 

 Figs. 7-11. — Pietitocystis Lialis. 



Fig. 7. — Cyst from Lialis containing three Cysticerci ( x 50). 



Fig. 8. — Longitudinal section of cyst ( x 100). /. I., fibrous outer layer of 

 wall ; h. I., homogeneous inner wall ; c. n., connective tissue 

 network ; ct., Cysticercus cut obliquely ; c. ct., cells attached to 

 inner lining of cyst and probably representing the first stage in 

 the development of a Cysticercus ; c. cp., columnar epithelium 

 of intestine. 



Fig. 9. — Invaginate Cysticercus, from a specimen preserved in Flemming's 

 Fluid ( X 80). 



Fig. 10. — Piestocystis Lialis with evaginated head; partly from living speci- 

 men ( X 50). 



Fig. 11. — Transverse section of invaginate Cysticercus at level of suckers 

 ( X 260). c, cuticle; s. c, subcuticula ; l.f. longitudinal fibres 

 of dermo-elastic layer; g. t., ground tissue; i. v., invaginati(m 

 cavity of head. 



Plate v. 

 Figs. 12-1,3. — Monocercus Didymogafstris. 

 Fig, 12. — Monocercus Didymogastris in optical longitudinal section ( x 250). 

 hi., "blastogen"; c. v., caudal vesicle; b., body; r., rostellum ; 

 s. r. , sheath of rostellum ; .<. , sucker. 



