DEVELOPMENT OF PERIPATUS NOV^l-ZEALANDl^. 237 



posterior to (hat shown in Fig. 21 c, but it is more highly magnified. End. 

 Endoderm. pr.g. Primitive groove, pr.st. Primitive streak. Oc. 2, obj. D. 



Fig. 23. — Surface view of a segmenting ovum, to show the yolk segmen- 

 tation. Ch. Chorion. T. S. Yolk segments. 



Fig. 24. — Surface view of a segmenting ovum. The protoplasmic segments 

 are seen lying on the surface of the egg. The yolk segmentation is not seen, 

 owing to the surface of the egg having been slightly disintegrated by the 

 preserving reagents. The chorion and vitelline membrane have been removed. 



Fig. 25. — An embryo, in which all the peripheral nutritive layer has 

 been absorbed, viewed from the side ; showing the large prseoral lobe with 

 the antenna budding out from it, and the lateral ridge with five distinctly 

 formed appendages (Ap.). 



Fig. 26. — The same embryo seen from the ventral side, and showing the 

 mouth and anus and primitive groove, in addition to the structures seen in 

 the last figure. These two drawings were from an embryo preserved in 

 picric acid. an. Anus. Ap. Appendages. ^.Antenna?. M. Mouth, p.o.l. 

 Prseoral lobe. pr. gr. Primitive groove. 



VOL. XXVIII, PART 2 NEW SER. 



