Along the Essequebo and Potaro. 127 



seen in the water, the pacu appears of a deep uniform 

 red colour, but, when taken out, the colouring is a dull 

 brownish purple, on which the red spots of the male are 

 extremely conspicuous. In shape they are much like a 

 large and thick oblong-bodied perai, but they have 

 teeth quite unlike those of the perai, being destitute of 

 the lateral cusps. 



Several specimens of different groups were obtained 

 at Pacoutout, and among them a large ring-tailed mon- 

 key (CebusJ. In the forest, too, for the only time 

 throughout the whole trip, snakes were met with. My 

 assistant came upon two, close to an old stump, one of 

 which, according to his account, darted towards him, but 

 received on the way the contents of his gun. The 

 head was almost entirely shot away, sufficient of it being 

 left, however, to prove that the animal was an innocuous 

 one, though with elongated and curved maxillary teeth at 

 the back of the upper jaw, which, to one with an insufficient 

 knowledge, would have been — and, perhaps, excusably 

 so — proof positive of the venomous nature of the creature, 

 as indeed they had been to my assistant. 



This snake, with much of the general shape of the 

 yellow tail (Spilotes corais) , was of a yellowish white 

 below and a dull leaden-blue above, which, in the sun- 

 light, gleamed literally with all the colours of the rain- 

 bow, especially at different points dependent upon the 

 curvature of the body in certain directions. From what 

 was left of the body, it seemed to be very similar to, if 

 not identical with, a rare Colubrid, which has the peculiar 

 characteristic of inflating its body to a large size when 

 irritated, and at the same time flattening out its anterior 

 part, horizontally, with a very striking resemblance to 



