PLATE I. 



Cl-AVA SQUAMATA. 



Pig. 



1. A male colony magnified. Tlie hydrantlis are seen, some fiiU^' extended, others in various 



states of contraction. 



2. The same, natural size, attached to a piece of Funis nodosus. 

 ;j. A cluster of female gonophorcs. 



4. A portion of the h3drantii -walls, after having undergone natural histolitic decom|josition, 

 very much magnified. The ectoderm is seen to the left, resolved into minute cell-like 

 elements, limited externally by a delicate structureless pellicle, and separated from the 

 endoderm by a layer of fibrillated (muscular) tissue. The endoderm is breaking up 

 into large spherical cells. 



5. A male gonophore. The spadix is surrounded by the spermatic mass. 



0. A female gonophore. A single ovum, with its germinal vesicle and germinal spot, lies on one 

 side of the spadix, which it has pushed out of the axis of the gonophore. 



7 — 11. Development of the embryo. 



7. The embryo still confined within the walls of the gonophore, from which it is ready to escape 



into the surrounding water. 



8. Embryos liberated as ciliated planulae from the gonophores. They are drawn in various 



positions which they are in the habit of assuming, and may be seen either fully extended 

 or more or less bent uj)on themselves. 



9. The planula, after it has lost its cilia and has become contracted longitudinally preparatory 



to fixing itself. 



10. The planula after it has become fixed and has developed a single verticil of tentacles. 



11. The 3'oung C7«z'fl still further developed. A second verticil of tentacles has been emitted 



at the proximal side of that first formed, the tentacles of the second verticil alternating 

 with those of the first ; a stolon has begun to be emitted from the base. 



