122 bulletin: museum of comparative zoology. 



satellite of America, with the added interest of being a stepping-stone 

 to the group of islands beyond it, some of whose ornithological features 

 it bears. 



Darwin, the first to study the birds of the Galapagos Islands, de- 

 scribed remarkable variations among them, even those inhabiting the 

 same island, that made it difficult to separate them specifically. New 

 forms brought to light by recent explorations, particularly those of the 

 " Albatross," have only served as links to connect the species still more 

 intimately, so that upon the Galapagos Islands there exists the most 

 remarkable grading together of species known to ornithology. This is 

 especially noticeable in the group of finches, in distinguishing which 

 arbitrary measurements are employed, some of the smaller forms closely 

 approaching Certhidea, a genus of the Ccerebidce. Into the gap between 

 these ( Cactornis and Certhidea) Cocornis from Cocos Island seems to fit. 

 The relationship of the Cocos Island flycatcher Nesotriccus is equally close 

 to Eribates inhabiting the Galapagos. In view of these facts, it is to be 

 regretted that our limited stay at Cocos Island did not permit of a more 

 thorough search for birds, as it is possible that other species exist in the 

 elevated central part of the island which we were unable to reach. 



The island is about four miles long by three wide, its central part 

 having an elevation of about 1,700 feet. It is everywhere covered with 

 the densest forest. Cocoanut trees are found upon the higher slopes, 

 and tree ferns abound in the ravines. No tropical forest could be more 

 dense and tangled. The rainfall is doubtless great, as each ravine con- 

 tains a dashing stream. It is a garden spot in comparison with the arid 

 Galapagos Islands. 



I am indebted to the kindness of Mr. Ridgway, Curator of Birds in 

 the National Museum, for much valuable information on the ornithology 

 of the islands of this region. 



COCOS ISLAND. 

 Dendroica aureola, Gould. 



Sylvicola aureola, Gould, Zool. Voy. Beagle, Part III. p. 86. 



Dendrazca aureola, Salv., Trans. Zool. Soc. Lond , Vol. IX. Part IX. p. 473. 



The two specimens of this warbler secured are not distinguishable from the 

 species (D. aureola) inhabiting the Galapagos. Only one other was seen. 

 The species is more closely related to D. petechia from Jamaica than the species 

 of the mainland. 



