18(j7.] the birds of the lower AMAZONS. r)[).'> 



Fam. Larid^-. 



280. Sterna magnirostris, Liclit. 

 Mexiana. 



281. Sterna superciliaris (Vieill.). 

 Rio Tocantins. 



4-282. Rhynchops melanura, Sw. 

 Mexiana. 



Having thus concluded our list of species, we proceed to consider 

 what conclusions can be drawn from it as to the general character of 

 the avifauna of the localities whence they are derived. Of the whole 

 number of 282 species, 48 are from the Rio Negro, and, as far as 

 our information goes, are not found in the Lower Amazons district. 

 From this part of the series, presenting us as it does with such an 

 insignificant portion of the whole ornis, it would be useless to at- 

 tempt to draw any further conclusion than that the large majority 

 of the species recorded from this region are Guianan forms. Of 

 the 48 Rio Negro species, 37 are certainly likewise found in Guiana. 

 The remaining 1 1 are believed to be either peculiar to the Rio Negro 

 or intruders from the Upper Amazonian district. These are — 



1. R(miphocoelus nigrigularis. /. Chordeiles rupestris. 



2. Pithys leucaspis. 8. Topaza pxjra. 



3. Piprajilicauda, 9. Eucephala hypocyanea. 



4. cyaneocapilla. 10. Capita amazonicus. 



5. Cephalopterus ornatus. II. Psophia ochroptera. 



6. Pharomacrus pavoninus. 



But these exceptions weigh little in the balance when we consi- 

 der the presence on the Rio Negro of such marked Cayenne types 

 as Gyjunoderus fcetidus, Gymnocephalus calvus, Rupicola crocea, 

 Xipholena pompadora, &c. 



Let us now, therefore, turn to the portion of the collection from 

 the vicinit}' of Para and the Lower Amazons, and see what results 

 can be derived from its examination. The whole number of species 

 obtained in these localities was 242, two of which cannot be satisfac- 

 torily determined at present. The remaining 240 may be analyzed 

 as follows : — 



1. Species of wide range, belonging to Cayenne, 1 ^.p 



Para, and South-east Brazil 



2. Species common to Para and Cayenne only, 



40 (16 per cent, of whole number); and 



species ranging west and north-west into \ 88 (about 61 per cent.) ^ 

 the Upper Amazons, Venezuela, New Gra- j j 



nada, and Central America, 48 ; together ... ) i 1 m 



3. Species common to Para and South-east Brazil 15 (about 10 per cent.) \ 



4. Species common to Para and Upper Amazons... 18 (about 12 per cent.) j 



5. Species found in Para alone 23 (about 1 7 per cent.) J 



1'4() 



The 96 wide-ranging species, which amount to about 40 per 

 cent, of the whole, comprise members of all orders, but are mostly 

 Proc. Zool. Soc— 18G;, No. XXXVIH. 



