OVUM IN THE CAPE AND NEW ZEALAND PEHIPATUS. 299 



which is present in the ovary itself. This yolk is most plentiful 

 just beneath the thin part of the ovarian wall, and is scarcer 

 just below the germinal epithelium. It is possible that this is 

 comparable to the condition found in Platyhelminthes, where 

 a special part of the female organs is occupied in the formation 

 of yolk^ while in the form Macrostomum (2), as in P. novse- 

 zealandisBj the function is actually performed in part of the 

 ovarian tube itself instead of a special gland being set aside 

 for it. I have no observations as to the origin of the small 

 amount of yolk in the Cape specieSj but this is of little interest 

 as it is obviously only a remnant of the large amount which is 

 present in the New Zealand species. 



List of Papers Referred to. 



(1) Balbiani, E. G. — " Sur I'origme des cellules du follicule et du noyau 



vitellin de I'oeuf chez les Geophiles," ' Zool. Anzeig.,' 1883. 



(2) Balfottk, F. M. — ' Comparative Embryology,' vol. i. 



(3) Beddakd, F. — " Observations on the Ovarian Ovum of Lepidosiren," 



' Proc. Zool. Soc.,' May, 1886. 



(4) Beneden, Ed. van. — " Recherches sur la maturation de I'oeuf et la 



Fecondation," 'Arch, de Biol.,' Tome iv, 1883. 



(5) Blochmann, F. — "Ueberdie Entwicklung der Neritina fluviatilis," 



Miili., ' Zeit. fiir wiss. Zool.,' Band xxxvi. 



(6) Caldwell, W. H. — "The Embryology of Monotremata and Marsu- 



pialia," Parti, 'Phil. Trans.,' 1887. 



(7) Cabnot, J. B. — ' La Cellule-Becueil de Cystologie et d'Histologie 



generale.' 



(8) FoL, H. — ' Recherches s. 1. Fecondation et 1. commen. d. I'Henogenie,' 



Geneve, 1879. 



(9) Gaffbon, E. — " Beitrage zur Anatomic u. Histologic von Peripatus," 



' Schneider's Zoologische Beitrage,' Bd. i. 



(10) Henking, H. — " Untersuchungen iiber die Entwicklung der Phalau- 

 giden," ' Zeit. f. wiss. Zool.,' xlv. 



