CEPHALOPODA. 



461 



an inch from the apertures, so that they appear to possess con- 

 siderable projectile and retractile powers. 



To the above forty tentacula must be added four others of a 

 different construction, which project immediately beneath the mar- 



gin of the hood, like antennae, one before and one behind each eye 

 (Jig. 212, r). These tentacles would seem at first sight to be 

 constructed upon the same principles as the last ; but, on examining 



