132 MR. O. SALVIN ON THE BIRDS OF VERAGUA. [Jail. 24, 



Nicaragua now stands, was open, tlie species of the northern portion 

 of South America and Costa Rica were identical, and but few neo- 

 tropical forms existed northward of the separation. 



A farther subsidence must then have isolated. Costa Rica, where 

 during a lengthened period most of the species have become slightly 

 moditied. A rise of land to the extent of the present contour of Cen- 

 tral America then took place. The old straits, now land, have been 

 occupied by contending allied races, sometimes the Costa Rican, and 

 sometimes the southern race prevailing, occasionally the southern 

 race penetrating through the country of its representative and driving 

 it before it. Towards the south the Costa Rican species have soon 

 met with their representative races, by which their range has been 

 staved ; while northward, impeded by no such barrier, they have 

 spread as far as climate and the supply of their necessary food would 

 allow them, the most strongly defined limit in this direction being, 

 probably, the nortliern boundary of th.c tropical virgin forest. 



-f-l. Catiiarus GiiiSEiCEi'S, Salviu, p. Z. S. 18GG, p. GS. 

 Santa Fe, Veragua. 



-f-2. Catharus fuscater (Lafr.). 



Myioturdus fnscuter, Lafr. Rev. Zool. 181.5, p. 341. 



Catharus fuscater, Sclatcr, Cat. A. B. p. 2 ; Salvin, P. Z. S. 186C, 

 p. 69. 



Cordillera of Tolc. 



Arce has sent a single male specimen of a Catharus which agrees 

 closely with Mr. Sclater's examples from Ecuador. The bill, how- 

 ever, is somewhat larger and, in this fresh specimen, of a brighter 

 orange-colour. C. fuscater is no doubt the southern representative 

 of C. mexicarais (Bp.) (Scl. Cat. p. 1), which occupies its place from 

 Costa Rica to Mexico. Both species are inhabitants of the " tierra 

 caliente,^'' and appear to be decidedly scarce in the countries in which 

 they are found. 



4- 3. TuRDUs GRAYi, Bp. ; Lawr. Ann. N. Y. Lye. viii. p. 1/4. 



Santa Fe, Veragua ; David {Hicks) . 



Ranges as far southv/ard as Panama. At Santa Martha T. luridus, 

 Bp. Notes Orn. p. 28, replaces it, a species of which I have recently 

 acquired a specimen, collected by the late Mr. Bouchard. This 

 differs from a Panama specimen of 2\ grayi in having the under 

 surface much paler, the crissum being nearly white. The upi)er 

 surface, too, is more olivaceous and hardly shows a cinnamon tinge, 

 the tail is squarer, and the dimensions, especially the feet, smaller. 

 Total length 9, wing 4 '5, tail 3-9 inches. 



-4-4. TuRDus LEUCAXJCHEN, Sclatcr, P. Z. S. 1858, p. 447; Baird, 

 Rev. Am. B. p. 24. 



Santa Fe and Cordillera de Tole. 



Veraguan specimens exhibit none of the marked characters which 



