2l8 



Edmund B. Wilson. 



Fig. V. 



Isolated Troclioblasts of Dcntalium and Mcsoblast-likc Cells of Patella 24 Hours: 



X 290. 



(All these obtained by leaving entire embryos in the calcium-free water for 

 24 hours). 



49-51, large (primary) trochoblasts; 52, 53, medium (secondary?) trocho- 

 blasts; 54, 55, small (secondary?) trochoblasts; 56, group of mesenchyme-Hke 

 cells; 57, group of muscle-like cells. 



