PLATE XVI. 



Fig. l.—Plethodon oregonensjs. From photographs of two alcoholic speci- 

 mens, showing the extremes of the swollen as compared with 

 the unswollen condition of the tail. 



Fig. 2. — From a photograph of a Living individual in process of regenerating 



the tail. 



Fig. 3. — From a photograph of a living individual in process of regenerating 



the tail. 



Fig. 4. — Cress section of the swollen tail, drawn with the camera lucida. 

 Enlarged 7\ times. 



i I'll . — Epidermis. 1. g. — Enlarged glands. 



Fig. 5. — Cross section of the skin of the unswollen tail, drawn with the 

 camera lucida under a low magnification. 



tl. g. — Discharged glands, n. g . — Newly-formed glands. 



Fig. 6. — Drawing finished from a pencil sketch. This shows the Plethodon 

 in the act of defending itself against Diadophis amabilis. 



