fi,y,K S (Sc.29; V.211 



C. 66) & hgr. (Sc. 26 



27 ; V. 204, 211 ; C. 71 



63). 

 .. Yg. (So. 26 ; V. 197 



C. 64). 

 f. 9 (Sc. 25; V. 190 



0.52). 

 i;. 5 (So. 25; V. 203 



0.64). 

 i. (J (Sc. 23 ; V. 194 



0.57). 

 X. tJ (Sc. 28 ; V. 205 



0.?). 

 K-u.. 3 (Sc. 23 ; V. 197 



0. 60), ? (Sc. 25 ; V 



206; 0. 64),&yg. (Sc 



25; V. 190; 0.63). 

 v,^,o. P(Sc.23; V.216 



0. 61) & hgr. (Sc. 23 



25; V. 204, 206; 



66, 51). 

 IT. 9 (Sc. 23; V. 195 



0.54). 

 p. Hgr. (Sc. 25; V. 194 



0.74). 

 <r-r. Yg. (Sc. 23, 25 



V. 207, 180; 0.58, 66) 

 V. Yg. (Sc. 27 ; V. 181 



0. 71). 

 ^. Hgr. (Sc. 33; V. 229 



C. 58). 

 X- d (Sc. 31; V. 225 



0.69). 

 ^jf. Skeleton. 

 a Skeleton. 

 a'. SkuU. 

 6'. Skull. 



This species may have to be united with the following. The 

 only character by which I have distinguished the two, viz., the 

 length of the keel on the dorsal scales, is not dependent on age or 

 sex, as had been supposed. Some specimens of L. lanceolaius, 

 however, approach L. atrox in the swelling of the scales at the 

 base of the keels, and are thus intermediate between the two sup- 

 posed species. It is also not impossible that two or three species are 

 confounded here under L. lanceolatws, but I have been unable to 

 trace any limits or to find any correlation between the modifications 

 in scaling and coloration. 



3. Lachesis atrox. 



Ooluber atrox, Linn. Mm. Ad. Frid. pi. xxii. fig. 2 (1754), and S. N. 



i. p. 383 (1766). 

 Vipera atrox, Imut. Syn. Bept. p. 103 (1768). 



