Vol. 32, pp. 213-216 December 31, 1919 



PROCEEDINGS 



OF THE 



BIOLOGICAL SOCIETY OF WASHINGTON 





TWO NEW CROTALINE SNAKES FROM WESTERN 



MEXICO. 



BY E. R. DUNN. 



Among the many reptiles brought back from Mexico by 

 Nelson and Goldman were three small snakes, two rattlers and 

 a Lachesis. The two rattlesnakes are obviously alike and appear 

 to be unnamed. So likewise the Lachesis seems to be hitherto 

 unknown. 



In naming these new snakes after Dr. Stejneger and Dr. Bar- 

 bour. I gladly take advantage of an opportunity to show my 

 appreciation of the advice and encouragement which they have 

 so often given me. 



Lachesis barbouri, sp. nov. 



Diagnosis. — A small Lachesis with single subcaudals, 17 rows of scales, 

 and an enlarged f ronta 1 shield. 



Range. — Omilteme, Guerrero, Mexico. 



Type. — United States National Museum, No. 46,347. Omilteme, Guer- 

 rero, Mexico. 



Description of type specimen. — Scales in 17 rows, the first smooth, the rest 

 keeled. Ventrals 154, anal entire, subcaudals 32 (23 single, followed by 

 three paired shields followed again by six single ones) . Tail apparently not 

 prehensile. Supraoculars large, separated across the head by three shields 

 of which the median is a large frontal and the lateral ones form part of a row 

 separating frontal from supraocular. Supralabials eight left, nine right — 

 none entering pit. Infralabials nine, three touching the one pair of geneials. 

 Two preoculars, four suboculars, two of which touch the third and fourth 

 labials and the last two of which are separated by one scale from the labials 

 — three postoculars. There are from one to three keels on the temporal 

 scales. Nasal divided — one scale between preocular and nasal, a large 

 scale in front of supraocular on top of snout. Canthus rostralis while dis- 

 tinct does not form an acute ridge as in L. godmani. 



Uniform dull olive above. On the posterior fifth of the body there are 

 indistinct light spots on the ends of the ventrals and on some of the scales 



44— Pboc. Biol. Soc. Wash., Vol. 32, 1919. (213) 



