^66 JORDAN, 



o 



PLATE XVIII. 



Fig. 52. Sagittal section through egg shown in Fig. 36 (X 48). 



Fig. 53. Transverse section through egg shown in Fig, 44. Thirty-seven 

 sections cephalad to Fig. 59 (X 200). 



Fig. 54. Transverse section through egg shown in Fig. 44. Thirty sections 

 cephalad to Fig. 53 (X 200). 



Fig. 55. Transverse section through an egg with circular blastopore ; blasto- 

 pore, however, much smaller than that shown in Fig. 36 (X 48). 



Fig. 56. Transverse section through egg shown in Fig. 45 ; near posterior 

 end of the embryo ( X 48). 



Fig. 57. Transverse section through egg shown in Fig. 45 ; thirty-two sections 

 anterior to Fig. 56 (X 48). 



Fig. 58. Horizontal section through stage between egg shown in Fig. 36 and 

 that in Fig. 37. Section is ventral to blastopore (X 48). 



Fig. 59. Transverse section through egg shown in Fig. 44. Eighteen sections 

 cephalad to Fig. 65 (X 48). 



Fig. 60. Transverse section through a stage between egg in Fig. 44 and egg 

 in Fig. 45. Hind end of embryo. 



Fig. 61. Transverse section at about the stage of egg in Fig. 45. Same 

 region as Fig. 60 (X 48). 



Fig. 62. Transverse median section through egg shown in Fig. 42 (X 48). 



Fig. 63. Horizontal section through egg shown in Fig. 40 (X 48). 



Fig. 64. Transverse section through egg of same stage as that depicted in 

 Fig. 44. Extreme anterior end. Position of cells forming "pouches" were 

 located with the camera ( X 48). 



Fig. 65. Transverse section through egg shown in Fig. 44. Hind end (X48). 



[The outlines of all the figures were drawn with the camera.] 



