APPENDIX A. 



Species examined, of which no specimens are in possession 

 op the simithsonian institution. 



CrotalUS oregonus, Holbr. — Grayish ash above, with narrow 

 lighter lines decussating, so as to form dorsal and lateral rhomboids, with 

 the angles all sharp and well defined, and their margins within the light 

 lines, black. Beneath black. The dark postocular vitta passes above the 

 labials without coming into the edge of the mouth. A light line across the 

 head through the middle of the superciliaries. 



Stn. Crotalus oregonus, Holbk. N. Amer. Herp. Ill, 1842, 21. PI. iii. 



The only known specimen of this strongly marked species, and 

 the same as that upon which Dr. Holbrook based his description, is 

 too much shrivelled to admit of accurate description. In its general 

 features it has a close resemblance to C. adamanteus, like it, having 

 the back crossed by decussating light lines, enclosing transversely 

 elongated rhomboids, with all the angles sharp and well defined. 

 Of these rhomboids there are about 32 from head to anus. 



The general color is grayish ash, the decussating lines being of a 

 lighter tint of the same. Along the margins of the lozenges, and just 

 within the light lines, is a black border. Scutellse black, with ash- 

 colored margins, the width of the ash-color diminishing from the 

 head to the tail. There is a narrow, well-defined line across the 

 head, just above the middle of the eye, which then appears to be 

 continuous along the edge of the superciliaries to the angle of the 

 jaw. A second white line starts between the nostril and the eye, 

 and, passing back under the eye, strikes the edge of the mouth at the 



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