PLATE II. 



Fig. 8. Cribrina elegantissima (drawn by Dr. G. N. Calkins). 

 9. Longitudinal section of upper part of the column wall 

 of Cribi'ina e/egantissima. cm = circular muscle at 

 apex of verruca ; ec = column ectoderm ; en = col- 

 umn endoderm; ve = modified epithelium at the apex 

 of the verruca (Leitz I, 3, camera). 



10. Transverse section of sphincter of Cribrina elegantissima 



(Leitz I, 3, camera). 



11. Tangential section of disk of Cribrina elegantissima 



(Leitz I, 3, camera). 



1 2 . Transverse section of tentacle of Cribrina elegantissima 



(Leitz I, 3, camera). 



13. Transverse section of siphonoglyphe of Cribrina ele- 



gantissiina (Zeiss a, Leitz I, camera). 



14. Transverse section of perfect mesentery of Cribri7ia ele- 



gantissima (Zeitz a, Leitz I, camera). 



15. Cribrina artemisia from a preserved specimen. Natural 



size. 



16. Transverse section of Cribrina artemisia (Zeiss a, Leitz 



I, camera). 



17. Anthopleura xanthogrammica (drawn by Dr. G. N. Cal- 



kins. 



( 50 ) 



