Castle. — Ciona intestinalis. 



PLATE X. 



Figs. 57-62. Surface views of preparations ; magnification, 560 diameters- 

 Fig. 57. 48-cell stage, viewed from behind. 

 Fig. 58. The same egg and stage, viewed from in front. 

 Fig. 59. 64-celI stage, ventral view. 

 Fig. 60. Tlie same egg and stage, dorsal view. 

 Fig. 61. 76-cell stage, ventral view. 

 Fig. 62. Tlie same egg and stage, dorsal view. 



JVote. — ^ Consult general statement under E.xplanation of Plates. The cell /A* 

 and its mate in tlie left half of tlie Figure were stippled by mistake. 

 Figs. 63-70. Eight cross-sections from a series through an embryo in late 76-cell 

 stage ; magnification. 560 diameters. For position of sections in em- 

 bryo, see horizontal lines 63-70 in Fig. 62. 

 Note. — In Fig. 63, the cells D'-^ and D*^-^* should be stippled like their mates. 

 In Fig. 67, the cell C^-" should be c"". 



