THE TWO-GILLED GROUP 



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Octopods comprise several families distinguished by differences in the general build, 

 the presence or absence of lateral fins, the number of rows of suckers on the arms, 

 variations in the radula, etc. Since the establishment of public aquaria, in compar- 

 atively recent years, most persons have had an opportunity of seeing the unsightly 

 octopus in its native element. An unpleasant, forbidding creature it is, contracting 

 and swelling, or looking like a shapeless but living mass. We observe the eight 



tapering arms, with two rows of suckers along the inner side of each, numbering 

 about two thousand altogether in some individuals. We note the two staring eyes 

 which seem ever on the watch, the funnel often exposed to view, and the mottled 

 skin. About ninety species of octopus are known, which occur in all seas. Varia- 

 tions in color, the relative length of the arms, the size of the suckers, and the 



characteristic of the hectocotylized or modified arm of the male, are among the 

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