THE VARIATION EXHIBITED BY ANCISTRODON HALYS (PALLAS) 
A PIT-VIPER INHABITING THE FAR EAST 
BY 
JOSEPH C. THOMPSON 
SURGEON, UNITED STATES NAVY 
CONTENTS PAGE 
Introduction _____ Arie senna op 5 = bone eeenes wee ue OW 
Variation in Number of Vertebrae Woh Gai sa we i oe ee 63 
Variation in Sum of Gastrosteges and Urosteges. Reeve et oe oer Oe 
Variation in Gastrosteges a a ee ae ee eg eee ser 64 
Variation in Urosteges Bat Ne dGu as ea oN os. ae O0) 
Variation in Seale Rows’ - aes a — as ada .65 
entsIRASINe eco 69 
Ussuri Province __. ee ee ORE us ewe eae es un uc OO 
Korea SE egy ere epee ey ee ere 69 
(GRR oe ee ee ere ok ge cae Oe 
Japan Re Aen ‘ Saat, Toole heen Oe 
Variation in Physiognomy : eerie ue bie ws: - Mee eee se tee eA 0) 
Variation in Prefrontals ; a ie ae eno bas ee Ota eae 70 
Variation in Frontals __ _- eee em eee aba ea was 70 
Variation in Postoculars _ eae ee ae a aie m5, ee Oa a ee 71 
Variation in ‘Temporals : a cnn ; : ie so ee vo tl 
Variation in Supralabials Rawk” Sd aks roan, oe) ad aaa i wate 
Variation in Infralabials oko ia eee ko : 72 
Summary of Variations Wada ae 6 ere a ee Ge i AS ses 10 
Position of Viscera_ sae os als . afd, 
Alleged Occurrence in the loca Chea titands < wo 10 
