SUCKERS OF A POULP. 



27 S 



Section of an arm and suckers of a 

 Poulp. 



e. Soft and tumid margin of the disk. 

 g. Circular aperture. 



the deeper waters, have to contend with the agile, slippery, and 

 mucus-clad fishes, more powerful organs of prehension have 

 been superadded to the suckers. 

 Thus, in the Calamary the base of 

 the piston is enclosed by a horny 

 hoop, the margin of which is de- 

 veloped into a series of sharp-pointed 

 curved teeth ; and in the still more 

 formidable Onychoteuthis each hoop 

 is produced into the form of a long, 

 curved, and sharp-pointed claw (/), 

 which the predacious mollusc presses 

 firmly into the flesh of its struggling 

 t ictim, and then withdraws by mus- 

 cular contraction. 



Besides the hooked acetabula, a 

 cluster of small simple unarmed 

 suckers may be observed at the base 

 of the expanded part. These add 

 greatly to the animal's prehensile 

 powers, for when they are applied to one another (e), the 

 tentacles are firmly locked together at that point, and the 

 united strength of both the elongated peduncles can be applied 

 to drag towards the mouth any resisting object which has been 

 grappled by the terminal hooks. There is no mechanical 

 contrivance which surpasses the admirable structure of this 

 natural forceps. 



The size of the arms and the arrangement of the suckers differ 

 considerably in the various species. In the octopods or poulps, 

 which generally lead a more sedentary creeping life, and, hidden 

 in the crevices of rocks, await the passing prey, the arms, in 

 accordance with their wants, are with rare exceptions longer, 

 more muscular, and stronger, than in the actively swimming 

 decapods, where the two elongated tentacles or peduncles are the 

 chief organs of prehension. In some species we find the arms 

 distinct — in others they are united by a membrane. Some 

 have a double row of suckers on each arm, others four rows, 

 others again but one. So wonderful are the variations which 

 nature, that consummate artist, plays upon a single theme — 

 bo inexhaustible are the modifications she introduces into the 



