6 



ST. JAGO CAPE DE VERD ISLANDS. Jan. 1832. 



series : the height of the difF thus affording a rude measure 

 of the age. 



During our stay, I observed the habits of some marine 

 animals. A large Aplysia is very common. This sea-slug is 

 about five inches long ; and is of a dirty yellowish colour, 

 veined with purple. At the anterior extremity, it has two 

 pair of feelers ; the upper ones of which resemble in shape the 

 ears of a quadruped. On each side of the lower surface, or 

 foot, there is a broad membrane, which appears sometimes 

 to act as a ventilator, in causing a current of water to flow 

 over the dorsal branchiae. It feeds on delicate sea-weeds, 

 which grow among the stones in muddy and shallow water ; 

 and I found in its stomach several small pebbles, as in the 

 gizzards of birds. This slug, when disturbed, emits a very 

 fine purplish-red fluid, which stains the water for the space 

 of a foot around. Besides this means of defence, an acrid 

 secretion, which is spread over its body, causes a sharp, 

 stinging sensation, similar to that produced by the Physalia, 

 or Portuguese man-of-war. 



I was much interested, on several occasions, by watching 

 the habits of an Octopus or cuttle-fish. Although common 

 in the pools of water left by the retiring tide, these animals 

 were not easily caught. By means of their long arms and 

 suckers, they could drag their bodies into very narrow cre- 

 vices ; and when thus fixed, it required great force to remove 

 them. At other times they darted tail first, with the rapi- 

 dity of an arrow, from one side of the pool to the other, at 

 the same instant discolouring the water with a dark chestnut- 

 brown ink. These animals also escape detection by a very 

 extraordinary, chameleon-like, power of changing their colour. 

 They appear to vary the tints, according to the nature of the 

 ground over which they pass : when in deep water, their 

 general shade was brownish purple, but when placed on the 

 land, or in shallow^ water, this dark tint changed into one of 

 a yellowish green. The colour, examined more carefully, 

 was a French gray, with numerous minute spots of bright 

 yellow : the former of these varied in intensity ; the latter 



