LIST OF ILLUSTRATIONS. 487 



Page. 



Fig. 50. — Head of Sisfi-uriis (atcnalus from side 412 



51. — Dorsal color pattern of Vrotalm moloHsus 422 



52. — Dorsal color pattern of Crotalus horridus 422 



53. — Dorsal color pattern of Crotalus confluenfus 422 



54. — Dorsal color pattern of Croia hts lepidus 422 



55. — Head of Crotalus from side 423 



56. — Head of Crolalns from front 423 



57. — Head of Crotalus Mitchellii from front 423 



58. — Color pattern of side of head of Crotalus adamantens 424 



59.— Color jiattern of side of head of Crotalus cotijtuentus 424 



60.— Color pattern of side of head of Crotalus luci/er 424 



61. — Diajiram of low rostral 424 



62. — Head of Crotalus lepidus from side 424 



63. — Diagram of high rostral 424 



64. — Head of Crotalus horridus from above. After Baird 428 



65. — Head of Crotalus horridus from side 428 



66.— Head of Crotalus cerastes from above. U. S. Nat. Mus., No. 482 451 



67. — Head of Crotalus cerastes from side 451 



68.— Head of Crotalus lepidus from side. U. S. Nat. Mus., No. 21057 , 453 



69.— Head of Crotalus Mitchellii from above. U. S. Nat. Mns., No. 12625.. 455 



70. — Head of Crotalus Mitchellii from side 455 



