498 Mr. P. R. Lowe — Observations 



the Honduratiu banks formed a chain of very closely con- 

 nected islands *, permitting the immigration of the original 

 Greater Antillean stock of the genus from Central America to 

 Jamaica, we can perhaps conceive that this line of emigration 

 would have missed Cuba altogether, and have pushed east- 

 wards in the direction of the peninsula of Jacmel in Haiti, 

 and from thence onwards through Puerto Rico to the Virgin 

 Islands. 



It may be objected that the distance between Jamaica 

 and Haiti from Cuba is so slight that such a proposition 

 seems unlikely. But in answer to this it must be stated 

 that the species comprising the genus Crereha are pecu- 

 liarly sedentary, and that there is little or no evidence that 

 they have ever extended their range by any other means 

 than land-bridges. Moreover, it must be remembered that 

 between Jamaica and Haiti on the one hand and Cuba on 

 the other there stretched Bartlett's Deep and the Windward 

 passage. In all probability this stretch of deep water would 

 have formed a formidable barrier to the passage of such a 

 sedentary race in even the greatest periods of elevation of 

 which we have any evidence in the West Indies. 



But whatever the possible explanation may be, we may 

 feel fairly certain, bearing in mind the great depression 

 obtaining in Central America and the West Indies in 

 Miocene times, that no extension of the genus from the 

 continent to the Greater or Lesser Antilles took place 

 before the early Pliocene elevation and possibly not before 

 the Pleistocene. 



II. Annotated List of the Species of the 

 Genus Ccereba. 



(Uereba Vieillot, Hist. Nat. Ois. Amer. Sept. 1807, tom. ii. 

 p. 70. (Type, Certhia flaveola Linn.) 



Ce?'thiula Sundevall, (Efv. Vet.-Ak. Ilandl. Stockholm, 

 1835, p. 99. 



* The Pedro bank, within fifty miles of Jamaica, after an elevation 

 of from 30 to 40 fathoms, would give an island 100 miles long, 30 miles 

 in breadth near its centre, and 45 miles at its western edge. 



