268 Wm. E. Hoyle, Cephalopoda. 2 68 



The Papulae of the ventral Arms (PI. Va, Figs. 12, 13). 

 The external surface of the ventral arms is covered by a mass of rounded papillae, averaging 0,3 mm 

 in diameter and aggregated into masses of a dozen or more. They are covered with epithelium closely 

 resembling that just described (Fig. 13 ep), below which is a mass of connective tissue raised up into a 

 heap in the centre of each papilla (Figs. 12, 13 c); it rests upon the subcutaneous muscle bundles (sm). 

 It is devoid of chromatophores. 



The ventral Mantle Patches (PI. Va, Fig. 14). 



The two oval patches on the ventral aspect of the mantle, above described, are very similar in 

 minute structure to the papillary areas on the arms. The epithelium is of the same character but between 

 its cells are found here and there deeply stained granulär cells, which appear to have undergone degene- 

 ration. The subjacent connective tissue resembles that below the papillae in having no chromatophores, 

 but differs from it in being traversed by large blood-vessels (v). As regards the function of these structures it 

 seems most probable that the dorsal papillae are protective. If these are anything like as erectile as is shown 

 in Ouoy and Gaimard's figure a surface could be produced, which might closely resemble an animal or 

 vegetable growth upon the rocks amongst which the animal lives. 



The other organs are probably similar in function, but it is difficult to suggest what this may be. 

 Nowadays in considering any problematic organ in a Cephalopod the first question is whether it may not be 

 a luminous organ. These structures, however, do not resemble any luminous organs which I have seen or 

 read of, and I am at a loss to find any more plausible Suggestion. 



