COMPARATIVE ANATOMY OF SOME BRITISH ACTINI/E. 



529 



and a fine, much-coiled spiral thread is faintly distinguished in one or 

 two cases. Near the base of the tentacle (Fig. 3) the endoderm is 



---end 



Fig. 3. — Sagartia ornata. Portion 

 of a transverse section from near 

 the base of a tentacle. 





Fig. 5. — Sagartia ornata. Vertical section 

 of the column wall, showing a portion of 

 the middle region of the sphincter. 



pb m.^- 



Fig. 4. — Sagartia ornata. Portion of a transverse section 

 through the column, showing two complete mesenteries 

 and two mesenteries of the third series. 



narrower and the nematocysts, although very numerous, are fewer in 

 number than above. The mesogloea is not strong and in some cases is 

 reduced to a fine strand. 



