456 WILSON. 
° EXPLANATION OF PLATE XIX. 
Fig. 61, Z. communis; Fig. 62, L. terrestris ; the others from Z. fetidus. 
Fic. 59. Superficial view of the posterior termination of the neural and nephric 
cell-rows of the left germ-band, showing the division of the neuroblast. X 700. 
Fic. 60. The primary mesoblasts and beginning of the mesoblastic rows in a speci- 
men of the same age as the last. X 450. 
Fic. 61. Superficial view of right germ-band, showing the four teloblasts; the 
nephroblasts dividing. X 375: 
Fic. 62. Similar view of left germ-band of Z. terrestris. X 375. 
Fic. 63. Diagram of the hinder part of the germ-bands of an embryo in the stage 
shown at Fig. 51. The bands are spread out flat, and all their elements are shown. 
The lateral cell-cord cannot be distinguished from the general ectoblast. X 250. 
Fic. 64. Superficial view of part of the left germ-band of Z. fetidus to show 
division of nephroblast. The nuclei of the superficial ectoblast are accurately drawn, 
and are seen directly to overlie the teloblasts and cell-rows. X 700. 
Fic. 65. Surface view of the germ-bands at a late stage at the point of divergence 
behind. Below the horizontal line the focus is quite superficial, in front of it the cells 
of the various rows are shown, separated here and there by deeper-lying ectoblast 
cells (e.c.). At the right appears the edge of the mesoblastic band (ms.) lying at 
a somewhat deeper level. The lateral cord is indistinguishable. X 400. 
(All the figures with the camera from preserved specimens. ) 
