436 CALIFORNIA ACADEMY OF SCIENCES [Proc. 4th Sf.r. 



of Bursera gravcolens above 1000 ft. (No. 416) ; Villamil, 

 common at 200-400 ft. Chatham Isl. : Wreck Bay, common 

 on the branches of trees and bushes in the neighborhood of 

 700 ft. (No. 417). Duncan Isl. : very abundant above 500 ft. 

 Indefatigable Isl. : Academy Bay, very abundant on 

 the branches of trees at 100-350 ft.; northwest side, 

 common on trees at 950 ft. (No. 420) ; southeast side, covering 

 trees and bushes at 350-550 ft. Jervis Isl. : very abundant 

 on small bushes, 450-750 ft. (no. 421). 



Arthonia Ach. 



A. gregaria (Weig.) Koerb. — Duncan Isl.: Snodgrass 

 and Heller. Not obtained by the Academy's expedition. 



A. nivea Willey — Galapagos Ids. : Hassler Expedition. 

 Not obtained by any of the more recent expeditions that have 

 visited the islands. 



A. platyspeilea Nyl. — Gardner Isl. (near Hood) : Snod- 

 grass and Heller. Not obtained by the Academy's expedition. 



A. sp. Willey — Galapagos Ids. : Hassler Expedition. 



Buellia De Not. 



B. straminea Tuck, in herb. — Albemarle Isl. : Christopher 

 Point, Snodgrass and Heller. Not obtained by the Academy's 

 expedition. 



B, sp. Farlow — Bindloe Isl. : Snodgrass and Heller. 



Chiodecton Ach. 



C. sanguineum (Sw.) Wainio — Abingdon Isl. : Snodgrass 

 and Heller. Duncan Isl. : sterile specimens were obtained 

 from the culms of grasses on the moister parts of the island 

 at about 1300 ft. (No. 422). Indefatigable Isl.: southeast 

 side, common on the trunks of trees above 650 ft. (No. 423). 

 James Isl. : James Bay, common on the trunks and branches 

 of trees in the neighborhood of 2000 ft., but was not noticed 

 some eight hundred feet higher up near the summit of the 

 island, (Nos. 424-425). 



