n ^ 



EXPERIMENTAL STUDIES IN GERMINAL LOCALI- 

 ZATION. 



EDMUND B. WILSON. 



II. EXPERIMENTS ON THE CLEAVAGE-MOSAIC IN 

 PATELLA AND DENTALIUM. 



CONTENTS. 



I. Introduction. Methods. 



II. Preliminary Notes on tlie normal Development. 



III. The Development of isolated Blastomeres. 



A. Analysis of the first Quartet. 



(i) General development of isolated micromeres of the first quar- 

 tet (la, lb, etc.). 



(2) The primary trochoblasts and their products (i^, i^.i^ 12.1.1^ 



etc.). 



(3) Development of the i^ cells (1/16). 



(4) Development of isolated apical cells and secondary trocho- 



blasts. 



(5) Development of the isolated entire first quartet. 



(6) Summary on the first quartet. 



B. Experiments on Cells of the lower Hemisphere. 



(i) The isolated i/8-macromere (lA, iB, etc.). 



(2) The isolated i/i6-macromere (2A, 2B, etc.). 



(3) The isolated second quartet-cells (2a, 2b, etc.). 



(4) Isolated cells obtained by maceration en masse. 



(5) Summary on the lower hemisphere. 



C. Development of isolated 1/2 and 1/4 blastomeres. 



(i) The partial cleavage in Doitalhim. 



(2) The partial cleavage in Patella. 



(3) The half and quarter larvae. 



IV. Summary. 



V. Discussion of Results. 



