n8 NATURAL HISTORY. 



is good reason to believe that most of the supposed cases of Octopus 

 attacking and drowning persons (like that of an Indian girl of the Oregon 

 coast, often cited) are merely instances of accidental drowning or suicides, 

 and that the presence of an Octopus is a post-mortem circumstance. Their 

 power and ferocity, as well as their size, have often been excessively 



exaggerated." 



The squids are characterized by a more cylindrical body and ten arms, 

 two of which may be greatly longer than the rest. Some are common 

 along the shore, while others are of rarer occurrence. Possibly the most 

 abundanl is the species figured here, which we may take as the type of the 



Fi(i. 10!). — A squid i Omtnastrephes illicebrosa) in the position it occupies in swimming back- 

 wards. The caudal fin is folded around the body, and the siphon, projecting below, is 

 directed forwards. Oue-half natural size. 



group. It occurs in large schools both north and south of Cape Cod, fol- 

 lowing the mackerel in their migrations and feeding on their young. Its 

 shape is shown in the cut ; its colors are very variable, and as one watches 

 a specimen they may be seen to change almost instantaneously. At one 

 moment the whole body will appear a dirty translucent white on which 

 by closer examination minute scattered black specks may be seen ; as one 

 watches, this will give way to a delicate rose-colored blush suffusing one 

 part of the body after another ; or perhaps giving way to shades of purple, 

 and then returning to the original translucent white. 



This change of color is highly characteristic, not only of this squid, but 

 of all the cephalopods. The mechanism can best be studied in very young 

 individuals, so small that they can be placed under the microscope. It is 

 then seen that the little black specks mentioned as visible on the white 

 surface are really subcutaneous sacs of pigment capable of great expansion 

 ;in<l contraction. When expanded to their fullest extent the layer of pig- 

 ment becomes much thinner, and as the adjacent pigment-sacs almost 

 touch, the color of the thin layer of pigment is given to the whole surface; 

 when the sacs contract a little, the color becomes darker. 



Squ'nls do not live well in confinement, yet in aquaria they show many 

 features which could not otherwise be studied. In this way one can 

 observe the changes of color described in the preceding paragraph, and 

 can also see the way in which they swim. The whole body up to just 

 behind the eyes is enveloped in a muscular sac-like mantle, while from the 



