292 
LILIAN SHELDON. 
21a, b, c. — July. Fig. 22. — July. Fig. 23. — December. 
Fig. 24. — December. Fig. 25. — July. Fig. 26. — July. 
This paper : 
Figs. 1 — 9. — January. Fig. 10. — July. Fig. 11. — July. 
Thus, speaking generally, the ages of the embryos received 
in the various months are : 
December. — Stages from unsegmented ova up to that 
at which nuclei were present at intervals just beneath the 
surface round about half the ovum. 
January. — From late segmentation up to gastrula stage. 
April. — Two embryos showing the beginning of the for- 
mation of the blastoderm, and also several stages with ecto- 
dermal yolk. 
July. — Stages in which the appendages are being formed 
up to embryos which were ready for birth. There were also 
newly-born young. 
Conclusion arrived at as to Time of Development. 
Probably the ova pass from the ovary into the uterus in 
December, and the young are born in July, the development 
thus occupying a period of about eight months. 
This, though apparently usually the case, cannot be universal 
since in each lot there were one or two females which con- 
tained embryos ready for birth, and also the embryos in one 
female vary somewhat in age. 
This statement as to the period of gestation has already 
been made by Mr. Sedgwick (3). 
List of Papers referred to. 
(1) Sedgwick, A. — “ The Development of the Cape Species of Peripatus,” 
Part II, ‘ Quart. Journ. Micr. Sci.,’ vol. xxvi. 
(2) Sedgwick, A. — “ The Development of the Cape Species of Peripatus,” 
Part III, ‘ Quart. Journ. Micr. Sci.,’ vol. xxvii. 
(3) Sedgwick, A.— “A Monograph of the Species and Distribution of the 
genus Peripatus,” ‘ Quart. Journ. Micr. Sci.,’ vol. xxviii. 
(4) Sheldon, L.—“ On the Development of Peripatus novse-zealandiae,” 
‘Quart. Journ. Micr. Sci.,’ vol. xxviii. 
(5) Sedgwick, A. — “ The Development of the Cape Species of Peripatus,” 
Part IV, ‘ Quart. Journ. Micr. Sci.,’ vol. xxviii. 
