Davenport. -- Crista tella. 



TLATE V. 



Figs. 40-43 are four horizontal sections of a polypide of Stage XII. passing in the 

 direction indicated by the lines 40-43, Fig. 18. X 300. 



" 44, 45 are horizontal sections of a polypide of Stage XIII. The direction of 

 the cutting planes is indicated by the lines 44, 45, Fig. 19. X 390. 



'■ 46-48. Sections through the migrating end of the funiculus, showing its rela- 

 tion to the coelomic epithelium of the roof. The ectoderm is not 

 shown. The arrow indicates direction of motion. X 390. 



" 49. Transverse section through the funiculus, showing the loose migratory 

 cells, x 390. 



" 50, 51. Horizontal sections of a polypide slightly younger than Stage XIV., 

 Fig 73. Of these two sections, Fig. 50 is nearer the roof of the colony, 

 and immediately above the ganglion. Fig. 51 is the second section 

 below, and passes through the middle of the ganglion. X 390. 



" 52. Sagittal section of the region about the brain of a polypide somewhat 

 older than that shown in Fig. 77. This figure is reversed relatively 

 to Fig. 77. x 600. 





