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As will be seen by the accompanying Plate, tbere are two forms of this Jacamar, differing in the 

 colour of the head, which in the one is green like the back, sometimes with slight bluish 

 reflections, in the other brown with narrow green edgings to some of the feathers. Not being 

 able to convince myself that this slight diversity indicates a real specific difference, I shall speak 

 of these plumages as the green-headed and brown-headed forms of the present species. 



The celebrated German naturalist Spix was the original discoverer of this Jacamar, during 

 his expedition to Brazil and up the Amazons in 1817 and the following years. In his well- 

 known work on the results of this journey, published in 1824, Spix described the present bird 

 as Galhula tomhacea, in allusion to its metallic colour, " tomback " in German being, I believe, 

 nearly the equivalent of pinchbeck, or of what is technically called red metal. Whether the 

 bird described by Spix belonged to the brown-headed or green-headed form of this species is not 

 quite certain. From his description it would appear that the former was the case ; but unless 

 my memory deceives me, the specimen in the Museum of Munich, supposed to be the type of 

 G. tombacea, which I examined some years ago, is of the green-headed form. 



In 1849 this Jacamar was redescribed by the French naturalist Deville under the name 

 " cyanescens," from specimens obtained by him during his descent of the Amazons in company 

 with M. de Castelnau. Here, again, there is some doubt to which of the two forms Deville's 

 name is properly referable. Though the description would indicate the brown-headed form, 

 Deville certainly obtained examples of both the green-headed and brown-headed birds, as I have 

 ascertained by the examination of his specimens in the Paris Museum. 



When I read my " Remarks on the Arrangement of the Jacamars " before the Zoological 

 Society in 1855, I had never seen examples of the brown-headed bird from the Amazons. 

 Finding that all the " Bogota " skins I had then met with presented this feature, I concluded 

 that they belonged to a different species, which I proposed to call G. fuscicapilla. Messrs. 

 Cabanis and Heine took the same view in their excellent memoir on the Jacamars published in 

 the 'Museum Heineanum' in 1853. They gave accurate descriptions of the brown-headed 

 (Bogota) bird as G. fuscicapilla, and of the green-headed bird as G. tomhacea, and retained also 

 the name cyanescens for the " apparently intermediate " Amazonian form, which they had not 

 seen. But I cannot follow this plan, because I have before me an Amazonian skin (from Pebas) 

 which I cannot in any way distinguish from the Bogota form, and have seen many other brown- 

 headed birds from Amazonia. On the whole it appears to me that the only way out of the 

 difficulty is to unite all the forms under one name, it being very doubtful whether either 

 " tombacea " or " cyanescens " could be legitimately applied to the green-headed form as distinct 

 from G. fuscicapilla. Having said thus much, I will now proceed to the general geographical 

 distribution of this species from north to south. 



G. tomhacea in the brown-headed phase is frequently met with in Bogota collections. But 

 it is probable that these skins are from the valleys drained by the upper affluents of the Orinoco 

 and Amazons south of Bogota, and that this species does not occur to the north of the Andean 

 range. On the Upper Amazons this Jacamar has been obtained subsequently to Spix's time by 

 Hauxwell at Pebas, and by E. Bartletf at Nauta. Such of Hauxwell's skins as I have examined 

 belong strictly to the brown-headed form, whereas those of Bartlett are green-headed and black- 

 chinned. The specimens from Eio Javari, which, although transmitted by Mr. Bates, were not, I 

 believe, collected by him personally, are somewhat intermediate in their characters, but perhaps 



