SYSTEMATIC ACCOUNT OF THE SPECIES. 193 



not much more than half the length of the parietals; loreal almost twice as 

 long as high; two pre- and two postoculars; temporals 1+2; eight upper 

 labials, the fourth only entering the eye ; four lower labials in contact with the 

 anterior chin-shields, three with posterior; posterior chin-shields a very Uttle 

 longer than the anterior and separated from each other by four scales; scales 

 keeled in nineteen rows; ventrals 163, anal divided, subcaudals fifty-seven. 



Colour (in hfe) : — Grayish olive above with dark slaty, almost black, 

 cross-bands, the first sending an extension forward to the posterior border of 

 the parietal shields; a dark streak on each side of the head; below bluish gray 

 marbled and flecked with whitish. 



This species is remarkably uniform in colouration. A few variations occur 

 among the head scutes, thus the preoculars may be fused into a single scale; 

 five instead of four lower labials may be in contact with the anterior chin-shields. 

 From various sources we find the range of counts to be ventrals 131-167; anal 

 divided; subcaudals 48-81. Boulenger (Cat. snakes, Brit, mus., 1893, 1, 

 p. 282) says: — 



"Olive or blackish aljove, with or without blackish cross-bands; a more or less distinct 

 light lateral streak on the second and third rows of scales; a dark streak on each side of the 

 head, passing through the eye; belly orange or red, dotted or spotted all over with brown 

 or browni dotted with pale." 



These remarks are very far from being in accord with our considerable experi- 

 ence of this snake in the field. We have never seen a blackish example, nor one 

 lacking the cross-bands, nor one with red or orange on the belly. Boulenger 

 had but three specimens before him when he wrote the Catalogue and they v/ere 

 probably badly preserved. The white lateral band, he mentioned, is always 

 found in the young, but we have never observed it on adults. In the young 

 also the dark cross-bands appear as oblong or squarish dorsal patches which 

 become extended into the strap-hke bands with increasing age. 



The Catibo or Quimbolo is wholly aquatic and also strictly nocturnal. By 

 day it may be found hiding beneath stones or in accumulations of drift vegeta- 

 tion, especially in the torrential mountain brooks. In these streams it occurs 

 quite abundantly, as in the more slowly flowing rivers or lagoons and lakes 

 choked with water plants. It is absolutely inoffensive and the largest indi- 

 viduals never open their mouths to bite when caught, nor offer the sUghtest 

 resistance. In the early morning or at dusk they may sometimes be seen partly 

 emerged from their lair, with their heads near the surface of the water. They 

 appear to breathe at the sm-face at very long intervals and we have never seen 



