on the Genus Coereba. 495 



inhabits the more northerly of the Lesser Antilles, repre- 

 sents a northerly extension of the Brazilian race (C chloro- 

 pyga). Probably it spread northwards along elevated land- 

 areas to the east of the ancient course of the Orinoco, a 

 supposition which is prompted by what we know in regard 

 to the land-shells of the more northern Lesser Antilles, 

 and the remains of large Pleistocene animals found in the 

 phosphate deposits of Anguilla (see Cope). 



Thus, regarded in the light of work done in relation to 

 the past geological history of the West Indies, Central and 

 South America (Gregory, Agassiz, Spencer, &c.), it is im- 

 possible to regard these two races which characterize the 

 genus as anything but quite distinct ; and to recognize such 

 subspecies as C. chloropyga luteola {cf. Ridgway, 'Birds of 

 North and Middle America,' pt. ii. p, 408 footnote) and 

 C. chloropyga mexicana [cf. Hellmayr, " Contri])ution to 

 Ornithology of Western Columbia/' Proc. Zool, Soc, 

 London, 1911, p. 1098), which combine representatives of 

 both races, appears to me to be scientifically indefensible, 

 or at least inadvisable. 



(G) Species from the Greater Antilles have both webs of 

 the lateral tail-feathers broadly and nearly equally tipped 

 with white ; while in South- American and Lesser Antillean 

 forms this white is more restricted on the inner web and is 

 reduced on the outer to the merest border. 



It is to be noted, however, that C. hananivora from Haiti 

 is an exception to this rule, for it conforms to the continental 

 arrangement, and the same remark also applies to C. saccha- 

 rina, as we have just seen. 



(7) The remarkable absence of any representative of the 

 genus from the island of Cuba and, having in view the 

 nature of the two countries, the less notable absence from 

 Yucatan and British Honduras. 



(8) The very interesting occurrence of melanic forms in 

 the islands of St. Vincent, Grenada, Los Testigos, and Los 

 Roques. 



(9) The remarkable effect that the mere isolation fur- 

 nished bv the West Indian Islands has had in fostering; the 



