514 ON TWO REMARKABLE SPOROCYSTS, 



13. — Thiky, L. — " Beitriige zur Kenntniss der Cercaria macrocerca Filippi." 



Zeitschr. f. wiss. Zool. 10, 1850. 

 14. — Thomas, A. P. — " The life-history of the Liver-fluke." Quart. Journ. 



Micro. Sci. 23, 1883. 

 15. — Ulicxy, J. — " Helminthologisehe Beitrage." Arch, f. Naturg. 44 



Jahrg. Bd. i. 1878. 

 16.— WaCtEner, G. — " Helminthologische Bemerkungen." Zeitschr. f. wiss. 



Zool. 9, 1858. 

 17. " Ueber Redien u Sporocysten." Arch, f, Anat. u. 



Physiol. 1866. 

 18. — ZiEGLEK, H. E. — "Bucephalus und Gasterostomum." Zeitschr. f. 



wiss. Zool. 39, 1883. 



EXPLANATION OF PLATES. 



Reference Letters. 



6r., brain. c, cuticle. ccZ. , disc at base of tail. f/.v.??i., dorso- ventral 

 muscles of tail, ex., principal excretory vessel. ^.r. &., excretory bladder. 

 i., intestine. I.e., lateral cells of tail, l.m., longitudinal muscles of tail. 

 Z.n., lateral nerve of tail, m., mouth, w./., muscular fibres developing in 

 myoblasts, my., myoblasts, o.d., oviduct, ce., cesophagus. ov., ovary, 

 jp^., pharynx, r., rudiment of gonads, .s'., anterior sucker, s". , posterior 

 sucker, sp. , spines, te. , testes. 



Plate 



XIX. 



-Sporocyst from Mytilus latus, magnified. 



-Sporocyst, entire preserved and stained specimen, somewhat com- 

 pressed ( X 75). 

 -Young stage of Sporocyst, compressed ( x 75). 

 -Young Sporocyst in the act of undergoing fission ( x 75). 

 -Ovary : appearance in entire specimen ( x 1000). 

 -Ovary: section, showing ova and early stages ( x 1000). 

 -Ovary : section next to that represented in fig. 6. 

 -Wall of Sporocyst : vertical section of one of the thickened regions 

 of the germinal epithelium ( x 1000). 

 Fig. 9. — Cercaria, magnified. The tail is here not so long in proportion as 



it is destined to become. 

 Fig. 10. — Body of Cercaria (with base of tail), showing excretory and diges- 

 tive systems. The posterior sucker is not shown. 

 Fig. 11. — Transverse section of tail ( x 750). 



Fig. 12. — Lateral view of a portion of the tail, showing the lateral line and 

 its nerve ( x 340). 



