BONES OF CUTTLE-FISHES. 233 



which it is built up. The common squid (Loligo 

 vulgaris) is also a decapod, two of its tentacles being 

 much longer than the rest. Like the sepia and others 

 of the same group, it possesses an internal bone or 



Fig. 163. 



Common Squid Pen of ditto. 



(Loligo vulgaris). 



"pen," the latter name being given to it on account 

 of its semi-transparent horny or quill-like structure. 

 This " pen" contains no limey matter. The Sepiola 

 Rondeletii is a much smaller cuttle, and addicted to 

 roving habits. It is not uncommon as an aquarium 



