91 Birds of the Islands of the Coast of Yucatan. 



stilbon forficatus alone can at present claim to be peculiar, 

 but both of them are also found on other islands. Holbox 

 and Mugeres therefore have a very decided mainland affinity 

 as regards their birds, a very slight peculiarity, and a West- 

 Indian element, due most probably to quite recent or not 

 distant casual immigration. 



Cozumel. — The larger size of Cozumel and the greater 

 time spent over the examination of its fauna gives us a total 

 of 159 species as found within its limits. Of these 65 are 

 migrants and 27 birds of very wide range. This leaves 66 

 as the number of resident species, with more or less restricted 

 limits ; 52 of these are also characteristic of the mainland, 

 4 are shared with other islands, 4 are strictly West-Indian, and 

 6 are peculiar. Of the latter, Spindalis benedicti is the only 

 one with West-Indian affinity, the others are modified main- 

 land forms. Harporhynchus ocellatus, one of these, is remark- 

 able as representing a genus not found nearer than the State of 

 Vera Cruz or the northern shore of the Gulf of Mexico. Its 

 presence in Cozumel must be attributed to casual introduc- 

 tion at a somewhat remote date, due perhaps to the severe 

 northern storms which prevail in this region during the 

 winter months. 



Thus Cozumel would seem to have been separated from 

 the mainland for a considerable period, during which time it 

 has received casual immigrants from the West Indies, from 

 North America, and from the mainland, some of them at 

 dates sufficiently long ago to allow of their modification. 



Ruatan and Bonacca. — These islands are very different 

 in their physical features from those just mentioned. They 

 are high, attaining an elevation of about 1200 feet, and have 

 the upper portion covered with pines, instead of being low 

 islands of recently elevated coral limestone. Mr. Gaumer's 

 collections from these islands include specimens of 72 species, 

 of which 42 are migrants, and 5 are of very wide range. The 

 remaining 25 also belong almost exclusively to the main- 

 land ; but there is a decided element amongst these, with an 

 affinity to the coast of Yucatan and its islands rather than 

 to the coast immediately opposite. This is shown by the 



