PLATE LI. 



Fig. 1. — Longitudinal section through the ectoderm, entoderm and 

 mesoglea of the peduncle at the base of a bud, showing the germ cells in 

 the ectoderm migrating toward the bud. 



Fig. 2. — Transverse section through the peduncle in the region of a 

 developing bud, showing germ cells in the entoderm. Stage A. 



Fig. 3. — Median longitudinal section through a medusa bud, showing 

 germ cells in the entoderm and the thickening of the ectoderm at the 

 apex. Stage B. 



ABBREVIATIONS FOR ALL FIGURES. 



B. Ent., Bud entoderm. 



Cav. Man., Cavity of the manubrium. 



Cav. Med., Cavity of the medusa. 



E., Egg. 



Ect., Ectoderm. 



Ect. Th., Ectodermal thickening. 



Ent., Entoderm. 



Ent. Man., Entoderm of the manubrium. 



Ent. Umb., Entoderm of the umbrella. 



Ext. Ect. Umb., External ectodermal layer of the umbrella. 



Ext. Glk., External layer of the "glockenkern." 



Int. Ect. Umb., Internal ectodermal layer of the umbrella. 



Int. Glk., Internal layer of the "glockenkern." 



G. C, Germ cell. 



Mes., Mesoglea. 



Nt., Nematocyst cell. 



R. C, Radial canal. 



S. C, Somatic cell. 



Spm., Sperm. 



