f 



\ 



2D2 JOURNAL OF CONCHOLOGY, VOL. 10, NO. 7, JULY, I902. 



In case of difficulty I shall at any time be glad to help my col- 

 leagues by examining Cephalopods from known British localities, if 

 they will send them to me. 



f A spiral chambered shell - - - Spinda perotii 



I No spiral chambered shell - - - - 2 



/' Ten arms and a fin - - - - - 3 



I Eight arms and no fin - - - - 23 



C Some of the suckers in the tentacular club pro- 

 3 ' vided with hooks - - Onychoteuihis b.mksi 



I None of the suckers provided with hooks - - 4 



Fin extending the whole length of the mantle, 



a hard internal dorsal shell {Sepia) - - 5 



Fin confined either to the end or to the middle 



of the sides of the mantle - - - 7 



Suckers on the sessile arms in two rows,' shell 



with no posterior spine - - - Sepia elegans 



Suckers on the sessile arms in four rows ; shell 



with a more or less prominent posterior spine - 6 



[ Breadth of mantle more than half the length (56 

 j per cent.) ; spine not very prominent - Sepia officinalis 



Breadth of mantle less than half the length (43 



per cent.) ; spine very prominent Sepi 1 07'bignyana 



Fins elliptical on either side of the middle ot the 



mantle ------ 8 



Fins beginning close to the hinder extremity of 

 the body and extending forwards a variable 

 distance along each side of the mantle - - 12 



Mantle fold continuous across the nuchal region 



iyRossia) . - . . . g 



Dorsal surface continuous with tliaL of the head 



in the middle line {Sepiola) - - - 10 



f Back smooth - - - Rossia macrosoiiia 



I Back papillate - - - Rossia glaiicopis 



Suckers in two rows on all the sessile arms - - 11 



Suckers in two rows except at the tip of the ven- 

 tral arms, where there are about four rows of 

 very minute suckers ; ink-sac tri-lobed or 

 eared - - - - Sepiola atlantica 



\ Ink-sac tri-lobed or eared - - Sepiola rondeleti 



\ Ink-sac pyriform - - - Sepiola scandica 



I In the middle portion of one or two arms there is often a tendency for the suckers to form 

 four rows, especially if the specimen is much contracted. 



8 -, 



