792 ^- E BEDDARD, On a new Sporozoen from the vesicul» of Perichaeta. 



List of papers referred to. 



1. Lankesteb, E. Ray, Article .Protozoa' in: Encvclopaedia Britannica, 



9'h Ed. 



2. BüTSCHLi, 0., Protozoa in : Brünn's Classen u. Ordnungen des Thier- 



reichs, Bd. I, 1882. 



3. Ruschhaupt , G. , Beitrag zur Entwickelungsgeschichte der mono- 



cystiden Gi-egarinen aus dem Testiculus des Lumbricus agricola, in : 

 Jen. Zeitschr. 1885. 



4. VAN Beneden, E., Sur une nouvelle espece de Gregarine designee 



sous le nom de Gregarina gigantea, in: Bull. Ac. Belg., t. 28 (1869). 



5. VAN Bbneden, E., Recherches sur Tevolution des Gregarines, in: Bull. 



Ac. Belg., t. 31 (1871). 



6. Schneider , Aimt , Contributions a Ihistoire des Gregarines etc., in : 



Arch. Zool. Exp., t. 4 (1875). 



7. Waldenburg, L., lieber Structur und Ursprung der wurmhaltigen 



Cysten, in: Arch. path. Anat., 1862. 



8. Greeff, R., Die Echiuren. in: Nov. Act. Leop.-Carol. Acad., Bd. 41 



(1879). 



9. Jackson, W. Hatchett, Forms of animal life, 2'** Ed., 1888. 



Explanation of Plate XXII. 



Fig. 1. Encysted form of Gregarine from seminal vesicles of a Peri- 



chaeta. 

 Eig. 2. Double cyst. 

 Fig. 3. Extremity of a stalle of a cyst. 

 Fig. 4. Tranverse section through d"; n nuclei of cyst. 

 Fig. 5. Contents of cyst in glycerine preparation. 

 Fig. 6. do. from a transverse section after staining with logwood : 



wj^nucleus. 

 Fig. 7. Extremity of the stalk of a cyst to show a, nucleus. 

 Fig. 8. Young stages of the same Gregarine. 

 Fig. 9. Newly formed cyst of do. 

 Fig. 10. Two individuals of stage 2. 



Fig. 11. Extremity of one of the processes of same highly magnified. 

 Fig. 1 2. First stage in transverse fission of mature unencysted individual. 

 Fig. 13. Second stage of the same. 

 Fig. 14. Dividing nucleus of encysted individual showing karyokinetic 



figures. 

 Fig. 15. Nuclei (n) and granules of entoplasm from section of encysted 



individual. 

 Fig. 16. Portion of an encysted individual undergoing division. 



