CHAP. XXII.] MOLLUSCA. 505 



Class.— CEPHALOPODA. 



Order I.—DIBRANCHIATA. 



Family 1.— AEGONAUTID^. " Paper Nautilus." (1 Genus, 



4 Species). 



Distribution. — Open seas of all warm regions. Two species 

 fossil in Tertiary deposits. 



Family 2.— OCTOPODID^. "Polypi." (7 Genera, 60 



Species). 



Distribution. — Norway to New Zealand, all tropical and 

 temperate seas and coasts. 



Family 3.— TEUTHID^. " Squids or Sea-pens." (16 Genera, 



102 Species.) 



Distribution. — Universal, to Greenland ; 2 other genera are 

 fossil, in the Lias and Oolite. 



Family 4.— SEPIAD^. " Cuttle Fish." (1 Genus, 30 Species). 



Distribution. — All seas : 4 other genera are fossil, in Eocene 

 and Miocene deposits. 



Family 5.— SPIEULID^. (1 Genus, 3 Species). 

 Distribution, — All the warmer seas. 



