SVENSKA EXPEDITIONEN TILL MAGELLANSLÄNDERNA BD II NIO 4. 59 



In studying this stränge structure and the peculiar 

 arrangement of the subcutaneous elements the question arises 

 to what nse is all this. I do not find the following explana- 

 tion quite satisfactory, but I think that it is an arrangement 

 of adaption with regard to the hydrostatic pressure, when 

 the animals descend to great depths. The papillse are rather 

 strongly innerved and provided with mnscnlar elements by 

 which the tension of the organ may be regnlated. It seems 

 therefore probable that it has, at least partly, a sensory 

 fnnction, and that this eonsists in helping the animal to 

 apprehend the strength of the hydrostatic pressure. But 

 I must confess that I believe that this subcutaneous tissue 

 ought to have some other fnnction as well, for it seems to 

 have too large an extension only to be a sensory organ. Its 

 distribution over the body like an external padding beneath 

 the skin of the whole surface of the mantle and the head 

 seems to allude to some protective fnnction. It is only the 

 fins and the arms that are not provided with this soft, 

 gelatinous and blubbery tissue, but perhaps an external layer 

 of this kind might on these parts be of hindrance in their 

 movements. But if it should be a protective layer it is not 

 easy to see against what. It would be very suitable as a 

 protection against high pressure and shocks the more so as its 

 softness or hardness may be regnlated by the contraction or re- 

 laxation of the musculature. But as it is just the same pressure 

 inside as outside the pallial cavity an exterior protective layer 

 is of no nse.* The same can be said with regard to the 

 teinperature as the same water which surrounds the body is 

 freely admitted into the pallial cavity. It could also possibly 

 be supposed that this layer might serve to increase or lessen 

 the bulk of the animal, but as the soft tissue is rather similar 

 to a fluid it cannot be very suitable in this respect either. 

 Against violent attacks of animals it cannot be of any 

 protective use as it is too loose for that purpose. But 

 the large quantity of oily fat which is storecl up in this 

 laver can be regarded as reserves. This latter fnnction as 

 a storage, together with the first mentioned sensory fnnction 

 is the only explanation which I can find plausible at present. 



* at least when the animal -and the surrounding medium is quiet; it 

 might however 1»' differenl when the animal moves by spurts. 



