132 The Cuttle-fish or Squid 



what they regard as a prey or an enemy, that is quite 

 disconcerting to observe in an invertebrate. But, 

 after all, what do we know of the intelligence of the 

 invertebrata ? 



The Octopoda, however, form but one small branch 

 of the amazing family of the naked Cephalopods, 

 whose home is in the deep sea, and whose breeding- 

 place is no one knows where. Their divisions are as 

 numerous as the range in their size is wide, and that 

 is from the tiny Loligo of a couple of inches in length, 

 to the gigantic Cuttle-fish, whose limit of size is un- 

 known, but of which specimens have been seen as big 

 as an adult sperm whale. Now these Decapods, or 

 ten-armed ones, are, though of the same family as the 

 Octopods, of widely different habits, and are also widely 

 divergent in shape. For instance, the Octopus has 

 a body very nearly globular in form, without a sugges- 

 tion of taper to it, while all the Decapods have a 

 cylindrical body, at the apex of which, or that part 

 remote from the head (which yet we can hardly call 

 a tail), is a sort of vane like that on a ship's patent 

 log just above the propeller. 



This vane has a definite purpose, now to be ex- 

 plained. It is obvious that no creature shaped like 

 the Cephalopoda, i.e., with a crown of long arms 

 branching out from the top of its head, can ever pro- 

 gress with any rapidity frontways, because the arms 

 would all spread out fan-wise, and prevent such a 

 manoeuvre. But the Squid or Decapod has that 

 matter arranged for. Its head wobbles loosely in 

 a wide collar of gristle, in one side of which there is an 

 orifice from which the creature can eject a jet of water. 

 When, therefore, it is necessary for a Cuttle-fish to 

 hasten away from the spot where it is, this hydraulic 

 jet is put in motion, and the ejected water comes out 



