11. LACHESIS. 533 



iSoaleg strongly keeled, in 13-15 rows ; 



Tenteals 134-143 ; subcaudals 48-56 . 30. rmerolepis, p. 560. 



B. Scales between the eyes smooth ; gular scales smooth ; first 



lower labial divided, the separate portion forming an pair of 

 small additional chin-shields ; scales feebly and obtusely 

 keeled ; ventrals 144-176 ; subcaudals 38-57 ; tail pre- 

 hensile. 



Scales in 21-23 rows ; second upper 

 labial usually not bordering the loreal 

 pit; 12-14 aeries of scales between' 

 the supraoculars 31. puniceus, p. 560. 



£cales in 19-21 rows ; second upper 

 labial bordering the loreal pit ; 10-11 

 series of scales between the supra- 

 oculars 32. borneensis, p. 561. 



C. Upper head-scales aU strongly keeled ; gular scales keeled ; 



scales more or less distinctly keeled, in 19-27 rows ; ventrals 

 127-154 ; subcaudals 45-55 ; tail prehensile. 



33. wagleri, p. 562. 



III. American species, with prehensile taU. 



A. Subcaudals all or greater part in two rows. 

 Scales in 27-35 rows; ventrals 198- 



218 ; subcaudals 59-71 34. Ulineatus, p. 565. 



Scales in 21 rows ; ventrals 149-171 ; 

 subcaudals 41-49 ; a horn-like scute 

 above the eye 35. undulatus, p. 565. 



B. Subcaudals all or greater part single. 



1. Supraocular shield narrow ; scales in 21-23 rows ; ventrals 



164-171 ; subcaudals 59-67. 

 loreal pit separated from the labials ; 



9 upper labials 36. lateralis, p. 566. 



Second labial forming the anterior border 



of the loreal pit; 10 or 11 upper 



labials 37. hicolor, p. 566. 



2. Supraocular shield large, separated from the eye by a series 



of pointed scales ; scales in 19-25 rows ; ventrals 138- 

 162 ; subcaudals 47-62 38. sehlegelii, p. 567. 



3. Supraocular shield large, bordering the eye ; scales in 19 



rows. 



5 or 6 series of small scales between the 

 supraoculars ; ventrals 134-146 ; sub- 

 caudals 49-54 39. nigroviridig, p. 568. 



An enlarged frontal shield ; ventrals 



154-158 ; subcaudals 53-61 40. aurifer, p. 568. 



