DEVELOPMENT Of PEfllPATTJS NOV^-ZEALANDIJl. 273 



List of Papers keferred to. 



(1) Sedgwick, A. — "A Monograph of the Development of Peripatus 



capensis." These Studies, vol. iv. 



(2) Sedgwick, A. — "A Monograph of the Species and Distribution of the 



genus Peripatus." These Studies, vol. iv. 



(3) Sheldok.L. — "On the Development of Peripatus novee-zealandiae." 



These Studies, vol. iv, pp. 230-262, 



EXPLANATION OF PLATES XXVII & XXVIII, 



Illustrating Lilian Sheldon's paper, " On the Development of 

 Peripatus novae-zealandiae." 



List of Reference Letters. 



Bl. Blastoderm. Btp. Blastopore, c. Cavity, corresponding to polar area 

 of P. capensis. Pm. A. Protoplasmic area. Pr. Gr. Primitive groove. 

 Pr. St. Primitive streak. 



All the figures were drawn with Zeiss's camera lucida ; Figs. 3 a and 9 were 

 drawn under Zeiss's oc. 2, obj. cc; Fig. 4 under Zeiss's oc. 2, obj. a; and 

 the rest under Zeiss's oc. 2, obj. b. 



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

 grown nearly half way round the yolk. 



Fig. 2. — Transverse section through the centre of an ovum, in which the 

 yolk is nearly covered by the blastoderm. 



Fig. 3. — Transverse section through an ovum, in which the primitive streak 

 is beginning to arise. 



Fig. 3«. — Transverse section through the portion of the same ovum which 

 is not covered by the blastoderm, drawn under a higher power. 



Fig. 4. — Transverse section through the centre of a young ovum before the 

 formation of the blastoderm, showing the multiplication of the nuclei in one 

 region near the periphery. 



