246 THE ORIGIN OF WEST INDIA BIRD-LIFE 



more peculiar genus than Cuba. The latter island is not only 

 ten times as large as Jamaica, but its proximity to Florida 

 has given it at least four forms which have evidently been de- 

 rived from Florida species. * * * Haiti and San Domingo, 

 although about seven times as large as Jamaica, have eight 

 endemic species less, while Porto Rico, nearly as large as 

 Jamaica and favorably situated for the reception of Lesser 

 Antillean species, has seventeen endemic species less than 

 Jamaica, and but one genus is peculiar to the island. 



" It is evident that, as Wallace has said, the islands ' were 

 not peopled by immigration from surrounding countries while 

 in the condition we now see them, for in that case the smaller 

 and more remote islands would be very much poorer, while 

 Cuba, which is not only the largest, but nearest to the mainland 

 in two directions, would be immensely richer, just as it really is 

 in migratory birds. 1 " (Distrib. Animals, Am.ed.,n,.1876, p. 66.) 



These facts in distribution and a study of hydrographic charts 

 give us some suggestive evidence in regard to a past land con- 

 nection between the West Indies and the mainland: Thus we 

 discover that an elevation of only 100 fathoms would leave but 

 two channels, the wider 75 miles across, between Jamaica and 

 the Honduras coast. Wallace, in theory, completely bridged , 

 this gap, connected Cuba with Yucatan, and filled the sea thus 

 enclosed with land, to which Sclater gave the name " Prseantil- 

 lesia ; " but, as Mr Agassiz has remarked : " The deep soundings 

 (over 3,000 fathoms) developed by the Blake, south of Cuba, be- 

 tween that island and Yucatan and Jamaica, do not lend much 

 support to the theory of an Antillean continent as mapped out 

 by Wallace, nor is it probable that this continent had a much 

 greater extension in former times than now, judging from the 

 depths found on both sides of the West Indian Islands " (1. c, 

 p. 116). 



While the disproportionately rich avifauna of Jamaica and 

 the shallow sea between this island and the mainland suggests 

 the possibility of a continental land connection at this point, the 

 absence of representatives of certain families of birds from the 

 Greater Antilles is opposed to the theory of this connection ever 

 having been complete. Thus, with the exception of Hadrostomus 

 niger in Jamaica and Colinus virgini.anus cubanensis in Cuba, the 

 following twelve families of Mexican and Central American birds 

 are without representatives in the Greater Antilles: Troglodytida?, 

 Pip'ridse, Cotingidre, Dendrocolaptidre, FormicariidaB, Galbulidre, 



