234 



CUTTLE-FISH, MOLLUSCA, ETC. 



object, although it gives some trouble through its 

 ink-discharging habits. Besides the above-mentioned 

 species, another octopus (Eledone cirrhosa\ having 

 only one row of suckers on its feet, is kept in most of 

 our public aquaria. 



Fig. 164. 



Sepiola Rondeletii. Pen of ditto. 



Although the cuttle-fishes and their allies are un- 

 doubtedly at the head of the mollusca a position 

 warranted by their specialised and perfect organs of 

 sight, brain (enclosed in a cartilaginous box, sug- 

 gestive of a skull), mouth, stomach, locomotive powers, 

 &c. they belong to one of the most ancient groups, 

 geologically speaking. We meet with some of their 

 ancestors in the Cambrian strata ; although the recent 

 type of cuttle-fish, with the hard parts internal in- 



