196 bulletin: museum of comparative zoology. 



Eecapitulation and General Remarks. 



We may now, in recapitulation, arrange in tabular form the differen- 

 tial processes which we have recognized. 

 I. Processes occurring in mesenchyme. 



1. Migration of nodal thickenings, p. 175. 



2. Free migration of amoeboid bodies, p. 176. 



a. from a layer. 



b. through fluid-filled spaces. 



3. Aggregation of mesenchyme, p. 176. 



a. into a thread. 



b. into a layer. 



c. into a- mass. 



4. Attachment of mesenchyme, p. 1 78. 



5. Investment and interpenetration, p. 178. 



6. Transportation, p. 179. 



7. Absorption, p. 180. 



II. Processes occurring in protoplasmic threads or tubules. 



1. Tropism, p. 181. 



2. Splitting, p. 182. 



3. Anastomosing, p. 183. 



4. Union with other organs, p. 183. 



III. Processes occurring in protoplasmic layers. 

 IIP. Processes affecting area. 



a. Processes occurring in the wall of a sac. 



1. Excessive growth of particular parts, p. 184. 



a. along one axis. 



b. at one pole. 



c. along one meridian. 



ji. Processes occurring in a plane or warped surface. 



2. Formation of perpendicular folds, p. 185. 



a. Pocket folds. 



b. Linear folds. 



3. Formation of folds in the plane of the area, p. 188. 

 IIP. Processes affecting thickness. 



4. Thickening, — general or local, p. 188. 



5. Thinning, — general or local, p. 189. 

 IIP. Processes affecting continuity. 



6. Atrophy, p. 190. 



7. Detachment of a piece from a layer, p. 190. 



