A Miv genus of SeriKiits, &fc. 189 



Sp. III. Heterodon tigrinus. 



Heterodon tigrinus. Colore cinereo cum maculis ovatis nl- 

 gris dorsalibus, aliisque maculis rotundis et nigris in utroque 

 latere. 



Scutis abdominalibus - - 133. 



Scutellis subcaudalibus - 52. 



Total length _ _ - - 161 inches. 



Tail - . . _ . 2i 



Head 1 inch, of which the large plates cover | 



The form of the dorsal scales, and the plates on the head, is 

 similar to that of the two preceding species; also the general 

 appearance is pretty much like the H. niger and H. annulaUis, 

 but it differs much in size. I never saw any specimen longer 

 than 16^ inches; all that I have seen were shorter. 



This species is very beautifully variegated : the generality 

 of the colours is black and ash gray : which is, in the young^ 

 ones, light, and in the old ones dark, approaching to brown. 

 A black stripe, commencing at the corner of the mouth, runs 

 in an oblique direction over the eye to above the little oval 

 plate ; where, crossing the head, it runs over the other eye to 

 the other corner of the mouth, forming a figure approaching to 

 that of the horse-shoe. Two black spots run from the two, 

 terminating large plates, diverging at first, but afterwards they 

 approach one another again. At the point where they are the 

 farthest apart is an elongated oval spot. These spots are re- 

 peated over the whole body ; they are about ~ of an inch long, 

 and are \ of an inch apart. On each side is a row of smaller 

 circular black spots, placed below the intervals between the 

 oval ones : this arrangement continues on to the tail, on which 

 the same colours are arranged in regular bands. 



The lower part is yellowish white under the head, gray under 

 the body, and white under the tail. 



