I'-iK. M. Il.^a.! ..I v;:,,ii.-. rnlMW'l. Al'l.-r HI. .eh. ITS'.'. T-.if. Ill, 



lit'. 1. 

 Fig. H2. Anterior portion of head, showing the arrarife'emciil 



of the hooks upon the roslellum. xl'lO. After Kiabtv. 



1869, Tab. VIII, ng. 154. 

 Fig. 8:i. Isolated hook. x920. After Krabbe, 1860, fls. ir.r,, 

 P'Ig. 84. Stroblla, natural size. After von Llnstow, 1872A, 



Taf. XXI, ng. 3. Host: Goosander. 

 Fig. 85. Head. x90. After von Llnstow, 1872A, Tat. XXI, fig. 5. 

 Fig, SS. Isolated hook. x5nO. After von IJnstow. 1872 A, Taf, 



XXI, fie, 2. 



Fg, S7, Knd of proglottid with cxtiudrd ctnii.s, xl.''.0. Aft.r 



von Llnstow, 3872A Taf, XXI. Ilg, 4, 

 Fig. 8S. Head of Taenia gracilis tadornae from the common 



sheldrake (Tadorna tadorna). After I,.onnberg, 1889, 



PI. I. figr, 1. 

 Fig, 89. Free cystlcercoid In the perch (Perca fluvlatills). x35n. 



After von Llnstow, 1872A, PI, XXI, fig, 1. 

 Fig. 90. Kxcretory system of the head and neck After Mrazek, 



1891. Tab, V, fig. 16. Zeiss .■!, D. 

 Fig, 91. Fnd cell of excretory system. After Mrazek, 1891, Tab. 



V. fig. 17. Zeiss 3, F, 



Plate Vni, Figis, 92-99.— Drt-panklotaenia gracilis, 



l'":g, 92, A cystlcercoid in process of development. A differen- 

 tiation Is noticed into the body and the tail, and a 

 small knob Is noticed on the anterior exlromity. The 

 6 oncospherl'C hooks are present in the tail. After 

 Mrazek, 1891, Tab. VI, flff. 25. 



Fig, 93. Another stage of the cystlcercoid. An invagination is 

 noticed on the anterior extremity; the middle portion 

 of the body Is occupied by a cavity filled with a 

 spongy tissue. After Mrazek, 1891, Tab. VI, fig. 26. 



Fig. 94. Cystlcercoid with the anterior portion of the tail: h., 

 peripheral hyaline layer; e., excretory canals; pr., 

 vibratory cells (see Pi. VII, fig), "Pronephrlostomes," 

 Zeiss 3, D. After Mrazek, 1891, Tab. V. fig. 13. 



Fig. <K,. Normal form of hook, Zeiss 3, F, After Mrazek, 1891, 

 Tab, V, fig. 14. 



Figs. 96-98. Three hooks, with variously arranged chitin. Zeiss 

 3, D, After Mrazek, 1891, Tab, V, fig. 15a-c. 



Fig. 99. A cystlcercoid with extended head: r., rostellum; c, 

 cyst: pr., tall with oncospheric hooks, Zei?s 1. D, 

 After Mrazek, 1891, Tab, VI, fig, 18, 



