66 Annals of the Carnegie Museum. 



Myospiza humeralis tneridana 

 j-Astragalinus psaltria columbianus 



AUitudinal Range. — In the above enumeration all the species not 

 known to range (in the Santa Marta region) above (approximately) 

 1,000 feet are preceded by an asterisk, while those not recorded be- 

 low this limit ^^ are designated by a dagger. Species without any sign 

 prefixed have been recorded from both belts, but comparatively few of 

 these have an altitudinal range coextensive with the recognized limits 

 of the Tropical Zone. Some of the forms in this category, however, 

 range upward into the Subtropical Zone and possibly even beyond. 

 Careful collation of the present list with the data obtained for the same 

 species in other parts of Colombia indicates that a considerable num- 

 ber of forms may very possibly go higher or lower than our present 

 information admits ; nevertheless, it is obvious that in the Santa Marta 

 region at least two divisions or belts may be recognized more or less 

 plainly in the area covered by the Tropical Zone. These belts depend 

 primarily upon altitude and humidity, and correspond in a general 

 way with the limits of the several kinds of forest already described 

 under the head of Ecological Conditions. Taking into consideration 

 the local distribution of the species of the Tropical Zone, therefore, it 

 has seemed advisable to divide the same into ( i ) the Littoral, or Lower 

 Tropical, comprising the coastal plain in general, the basin of the 

 Magdalena, the valley of the Rio Cesar, and the lower reaches of the 

 foothills encircling the mountains, up to an altitude of (more or less) 

 i,ooo feet above sea-level; and (2) the Piedmont, or Upper Tropical, 

 embracing that part lying above this elevation, extending to the upper 

 limits of the Zone. 



The distinctions which we thus recognize are not to be regarded 

 as comparable with the zonal subdivisions known as faunas (using this 

 word in its restricted sense), but rather imply that the Tropical Zone 

 is not altitudinally homogeneous. There is considerable evidence 

 (some of which we hope to present in another connection) going to 

 show that such a grouping of species as is here indicated is by no 

 means peculiar to this particular region.- Nevertheless, we agree with 

 the latest authority on the subject that no formal division of this zone 

 should be attempted on this basis alone. With this understanding, 

 therefore, we proceed to a fuller consideration of the 



12 Except as stated beyond (page 69). 



