18 



18 mm. in diameter. From heir they steadily decrease 

 again, towards the tip becoming nlmost too small for the 

 naked eye to distinguish. The pressure they exert is very 

 great, and must render the prey completely helpless. 

 Even when only clinging to the hand with one tentacle, 

 Eledone can hold on firmly enough by sucker action to 

 enable one to lift the creature bodily out of the water. 

 "Frequently the skin is shed from the surface of application 

 of the sucker. 



Sj?h. 



I nil. }\ 



Br. A. 



ext. 



Fig. 1H («) Trans, sect, distal 

 part <>f arm showing relation 

 of sucker (S). 



Fig. Ill (b) Sagittal sect, of 

 sucker of Argonauta. 



Fig. lllfl. 



Text iig. Ill if, shows a diagram of a transverse 

 section through the arm, indicating the relation of the 

 sucker to the remaining muscles. Ill b, is a modification 

 of Niemiec's figure of the sucker of Argonavta. The 

 outer surface of the sucker is covered by the general skin 

 of the arm. The inner lining is a much folded 

 epithelium, which covers the inner and outer divisions of 

 the adhesive cup (III a, II and I). A sphincter muscle 

 (SpJi.) tends to close 1 the upper and lower cups off from 

 one another, and tins muscle is opposed by the vertical 

 extensor muscle (III b, eat.). When the sucker is applied 



