486 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 
18mm. in diameter. From here they steadily decrease 
again, towards the tip becoming almost 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, 
Kledone 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. 
Sph. 
Sph, ~---+- 
ba e 
-- Arm 
ols Mus. Fic. IIIb. 
Br AN, ; 
Fie. III (a) Trans. sect. distal 
part of arm showing relation 
of sucker (S). 
Arm. V, : 5 
Fic. II (b) Sagittal sect. of 
sucker of Argonauta. 
Br. A 
Hires lita: 
Text fig. III a, shows a diagram of a transverse 
section through the arm, indicating the relation of the 
sucker to the remaining muscles. III 6, is a modification 
of Niemiec’s figure of the sucker of Argonauta. 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, Il and I). <A sphincter muscle 
(Sph.) tends to close the upper and lower cups off from 
one another, and this muscle is opposed by the vertical 
extensor muscle (IIT 4, eat.). When the sucker is applied 
