ILLUSTRATIONS. 



TEXT FIGUEES. 



Fig. 1. Traasverse section of a tentacle of Lima sp. Im, longitudinal muscle 

 bundles; n, nerve; rm, radial muscles. Original. 



2. Transverse section of a cerus of 'Nautilus pompilius. A, arteiy ; CM, 



circular muscle layer; E, thickened epithelium on inner surface; LM, 

 LM', longitudinal muscles; A^, nerve; OM, oblique muscle layer; RM, 

 ?adial muscles ; TM, transverse or radial muscles ; V, vein. ( From 

 Griffin, Anatomy of Nautilus pompilius. ) 



3. Longitudinal section of a pallial tentacle of Lima sp. Original. 



4. Longitudinal section of the tip of a cirrus of Nautilus pompilius. (From 



Griffin, Anatomy of Nautilus pompilius.) 



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