1 ) a v en port. — Cristatelia. 



PLATE III. 



All figures are magnified 390 diameters. 



Fig. 16. A later stage (VI.) in the direct t} r pe of bud formation. The mother polyp- 

 ide is cut to one side of its sagittal plane, and shows the invagination 

 of the lophophore arm (br. toph.). The funiculus appears as scattered 

 cells about both buds. 



" 17. A still later stage in the same series as Fig. 10. The daughter bud (VII.) 

 has a lumen. In the mother polypide (XL) the atrium has enlarged 

 by the inshoving of the lophophore arms. The oesophageal and rectal 

 invaginations are not yet continuous, and the ring canal (can. crc.) has 

 begun to appear oralward in the sagittal plane. Sagittal section. 



" 18. Stage XII. Alimentary tract nearly complete. Beginning of the forma- 

 tion of the ganglion. One of the lophophore arms is cut tangentially. 

 Sagittal section. 



" 19. Stage XIII. Ganglion closing. The lophophore arm cut tangentially. 

 Sagittal section. 



" 20 and 21. The positions and directions of the planes of these sections are 

 shown by their projections on a sagittal section (Fig. 11, lines 20, 21) 

 of an individual of the same age. To show non-participation of the 

 outer layer in the first stage in formation of the alimentary tract. 



" 22. Early stage in direct bud-formation. Origin of funiculus, cl. fun. Sagit- 

 tal. Margin to right. 

 23. The position and direction of the plane of this section are shown by its 

 projection on a sagittal section (Fig. 19, line 23) of an individual of 

 the same age. This figure shows the folds of the inner layer at the 

 mouth of the ganglionic sac. 



