17 



counting ventrally from the dorsal surface. The arms are 

 Ion o , flexible tapering cones, slightly compressed 

 laterally, and closely connected at their bases, to form a 

 circular cireumoral crown round the Buccal Mass (PI. I, 

 fig. 1, Br. app.). The bases of the arms are connected by 

 a membranous semi-transparent Aveb which extends for 

 about one-fifth of the Length of the arm, as an inter- 

 brachial membrane. Further along it is continued as 

 lateral wing's — one on each side of each arm — which 

 gradually diminish in size, and towards the distal end of 

 tlic arm can uo longer be distinguished (PI. 1, fig. 1, II .). 

 This web is characteristic of the family Octopodidae, to 

 which Octopus and Eledone both belong. Measuring the 

 two dorsal arms and the body of half a dozen specimens of 

 Eledone, it is found that the relative length of the arm, 

 to the head and body, is 22!) mm. to 113 mm. or roughly 

 2 to 1. there are about eighty suckers on each arm, 

 arranged in a single row. They have no horny ring, and 

 thus differ from the suckers in flic Decapoda. Also they 

 are much shallower, and none are modified into hooks. 

 The suckers in Eledone are sessile, but the surface of the 

 arm which supports them is raised up beneath each sucker 

 into a flexible cylinder which really acts as a stalk, and 

 allows if to move freely about. Successive suckers are" 

 separated from one another by a slight space. It is 

 noticeable that when these suckers are applied to any 

 surface, they do not keep in one straight row, but become 

 displaced laterally so as to give the effect of several 

 irregular rows of suckers on the arm. The sucker nearest 

 to the mouth is about 3 mm. in diameter in a larjje 

 specimen, and equals in size those about half-way down 

 the arm. At first they increase in size working from the 

 mouth towards the tip of the arm, and the fifth and sixth 

 suckers are the largest which occur — about 12 mm. to 



