DR. E. B. WILSON ON THE DEVELOPMENT OF RENILI|A. 
ps. Peduncular septum. 
8. Septa. 
s.l. Supporting lamella. 
sp. Spicule or spicule cell. 
st. Stomodeeum. 
t. Tentacle. 
v. Ventral chamber or ventral side. 
vs. Ventral septa. 
v.ce. Ventral (ventro-lateral) calyx-teeth. 
vf. Ventral mesenterial filaments. 
v.ls. Ventro-lateral septa. 
v.l.f. Ventro-lateral mesenterial filaments. 
v.l.ch. Ventro-lateral chamber. 
y. Yolk. 
Z. Inhalent zooids. 
PLATE 52. 
809 
. 1 to 14. Segmentation of an egg which divides at first into eight spheres. Time 
as follows :—Fig. 1, 8.50 A.M.; 2, one minute; 3, two m.; 4, seven m.; 
5, ten m.; 6, twenty-five m.; 7, thirty-four m.; 8, fifty-five m.; 9, sixty- 
three m.; 10, sixty-eight m.; 11, seventy-five m.; 12, ninety m.; 13, ninety- 
eight m.; 14, one hundred and fifteen m, 
15 to 18. Continuation of segmentation, from another specimen. 
X 85. 
Time as 
follows :—Fig. 15, 10 a.M.; 16, ten m.; 17, twenty-seven m.; 18, thirty- 
twom. X85. 
. 19 to 24. Unusual mode of segmentation. 
Time as follows :—Fig. 19, 
7.55 A.M.; 20,twom.; 21,tenm.; 22, twenty m.; 23, twenty-three mrs 
24, forty m. X65. 
. 25 to 27. Division of an egg into two spheres. 
. 28, 29. Ege divided into four spheres. x 65. 
PLATE 53. 
Time not recorded. x65. 
xX 65. 
. 38 to 41. Unequal segmentation beginning with sixteen spheres. 
. 80 to 37. Segmentation of an egg which divided at once into sixteen spheres. 
Time as 
follows :—Fig. 38, 9.7 A.M.; 89, same in different position; 40, thirty- 
three m.; 41, thirty-six m. X65. 
. 42 to 44, Another specimen illustrating unequal segmentation beginning with 
