DEVELOPMENT OP PERIPATUS NOV^-ZEALANDLE. 233 



Fig. 1. — Transverse section through an unsegmented ovum, in which the 

 nucleus is at some little distance from the periphery. The yolk is unsegmented. 

 n. Nucleus. Y. Yolk. Pm. Protoplasm surrounding the nucleus. Oc. 2, 

 obj. B. 



Fig. 2. — Section through a small portion of an unsegmented ovum, showing 

 the nucleus situated close to the periphery, n. Nucleus. Pm. Protoplasm 

 surrounding the nucleus. Y. Yolk. V. m. Vitelline membrane. Ch. Chorion. 

 Oc. 2, obj. D. 



Figs. 3« and 2>b. — Transverse sections through an ovum, in which two 

 nuclei are present, and in which the yolk has not begun to segment. 



Fig. '6 a passes through one nucleus, which is situated at the periphery of 



the egg, and has a lobed form. 

 Fig. 3 b passes through the other nucleus, which is at the same pole as 

 that in Fig. 3«, but lies deeper in the egg. It is in a state of division, 

 the section passing transversely through the spindle, n. Nucleus. 

 Pm. Protoplasm surrounding the nucleus. Y. Yolk. Oc. 2, obj. B. 

 Figs. 4<z — c. — Three transverse sections through an ovum containing three 

 nuclei, and in which the yolk has begun to segment. 



Fig. 4# shows the whole egg. At one pole a round nucleus is present, 

 and the yolk has begun to segment, the yolk-spheres at that pole 

 being smaller than over the rest of the egg. Oc. 2, obj. CC. 

 Fig. 4£ shows only the pole of the egg containing the second nucleus 

 and the yolk segmentation. The nucleus is much lobed. Oc. 2, obj. D. 

 Fig. 4 c passes through the third nucleus, and shows only a small portion 

 of the egg. The nucleus is lobed and very irregular in shape, n. 

 Nucleus. Pm. Protoplasm surrounding the nucleus. Y. Yolk. Y. S. 

 Yolk segments. Oc. 2, obj. D. 



Fig. 5. — Transverse section through the protoplasmic pole of the ovum, 

 which is shown in surface view in Fig. 24. The protoplasm is seen to consist 

 of a reticulum, in which the nuclei lie irregularly, n. Nuclei. Pm. Proto- 

 plasm. Y. S. Yolk segments. Oc. 2, obj. CC. 



Fig. 6. Section through a small portion of the protoplasmic pole of the 

 same egg as Fig. 5, highly magnified, to show the irregular arrangement of 

 the nuclei, twelve of them being closely packed together in a small reticulate 

 area of protoplasm. Oc. 4, obj. E. 



Fig. 7 a. — Transverse section through the protoplasmic pole of an ovum, 

 slightly older than that from which Figs. 5 and 6 were drawn, showing how 

 the protoplasm has spread over a larger portion of the surface of the egg ; it 

 still forms a perfectly continuous reticulum. Oc. 2, obj. D. 



Fig. lb. — Section through the same ovum near the limit of the protoplasmic 

 area, to show how the protoplasmic areas are connected together by strands. 

 Oc. 2, obj. D. 



