BY E. M. JOHNSTON, F.L.S. 



69 



(i.) Family Octopodid^i. 

 Mantle supported by fleshy bands ; no ceptralic aquiferous 

 pores ; arms subulate, elongated, more or less united 

 by webs, their suckers sessile. 



SYNOPSIS OF GENEKA. 

 (1.) Arms with two rows of suckers Genus. 



(a.) Body not finned. 

 Body rounded ; arms long ; suckers 



sessile ; third right arm of male 



hectocotylised Octopus (1.) 



Differs from Octopus in having a small 



aquiferous system, consisting of 



a bag with a small pore at its 



lower edge upon the web between 



each arm Cistopus ( — ) 



Body oval, wider than head ; arms short ; 



cups with narrowed bases ; third 



left arm hectocotylised Scseurgus ( — ) 



Arms united by a web nearly to the ends Alloposus ( — ) 



(&.) Body Finned. 

 Body like Octopus, but finned ; arms 

 with two rows of suckers 



(2.) Arms with a single row of suckers 

 (a.) Not Finned. 

 Body rounded, without fins ; third right 



arm hectocotylised 

 More gelatinous than Eledone ; suckers 

 smaller, less developed 



(6.) Finned. 

 Body with two transverse medial fins ; 

 mantle united to the head nearly 

 all round by a conical band ; 

 arms united by a web nearly to 

 the tips 



(3.) Arms with three rows of suckers. 

 Body not finned, Trixaxeopus ( 



Pinnoctopus (2) 



Eledone ( — ) 

 Bolita?na ( — ) 



Cirroteuthis ( — ) 



-) 



(ii.) Family Aegonautidte. 



Mantle supported by two buttons fitting into grooves at the 

 base of the siphuncle ; the two upper or dorsal arms 

 (in the females only) expanding into broad webs at 

 their extremity, -from which an egg-nest (shell) is 



