on the Genifs CoKreba. 517 



arrangement characteristic of continental species of the 

 genus and the ashy white of the throat is not continued 

 nearly so far back as in C. hahamensis. 



Unless tlie winter climate of Cuba is of such a nature 

 as to negative the existence of tlic genus upon it, it is 

 difficult to believe that birds carried by the trade-winds 

 from the Bahamas could have established themselves on 

 Cozunicl (or the Caymans) without also colonising Cuba. 

 As it is, there seem to be no records of even casual stragglers 

 from the latter island. Indeed, in all the West Indian 

 Islands I have never met with an alien species, and have 

 only come across a single instance of this in records, viz., in 

 the case of an example of C luteola having been described 

 as a new form in Grenada under the name of C. godmani. 

 My impression is that in the case of this very sedentary 

 genus the only channels by which the West Indian Islands 

 were originally colonised was by way of ancient land- 

 connections only. 



It therefore seems more likely tliat C caboti, C. nharpii, 

 and C tricolor are insular relics of a ( ■entral-American race 

 which flourished at some period wdien Central America con- 

 sisted of a series of large islands. Chapman (Bull. Amer. 

 Mus. Nat. vol. iii. 1896, p. 273) states that there are 

 "from fifteen to twenty forms peculiar to Cozumel. As 

 might be supposed, the larger number of these are derived 

 from the contiguous mainland (ten miles distant); but one 

 species has no close relative nearer than Panama, another is 

 not represented, even generically, nearer than Vera Cruz 

 (Mexico), while several are representatives of genera peculiar 

 to the West Indies." It seems probable therefore that 

 Cozumel did not share in the submergences which have 

 affected Yucatan. 



CffiREBA TRICOLOR. 



Certhiola tricolor Ridgway, Proc. U.S. Nat. Mus. vii., 

 July 29, 1884, p. 178 (Old Providence Island, Caribbean 

 Sea ; Coll. U.S. Nat. Mus.). 



Hah. Old Pi-ovidence Island, Caribbean Sea. 



.3 c^ J & ? ? . Coll. Brit. Mus. 



2 N- 2 



