44 VOYAGES OF A NATURALIST 



nearest available hole. They were aU of a pale 

 saffron colour, and the largest we were able to 

 catch was not more than four inches across the 

 carapace. 



The higher up the ravine we climbed, the more 

 abundant the dead trees became. In all of them, 

 as well as on the rocks which were scattered about 

 on the sides of the valley, white terns were nesting 

 in great numbers. I knocked over several with a 

 stick, and at once noticed that they belonged to a 

 different species to those obtained in the South 

 Pacific during our first voyage. The bill of these 

 Trinidad birds was whoUy black, while that of 

 the Pacific and Indian Ocean birds has a base of 

 a hyacinth-blue colour. There are also other less 

 noticeable differences between the white terns of 

 South Trinidad and those of the Pacific Ocean. 



On our return to England, and after a thorough 

 examination and comparison, I had the pleasure 

 of describing as a new species this lovely little 

 tern of South Trinidad, and naming it after Lord 

 Crawford {Oygis crawfordi).* There was only one 

 other specimen of this bird from South Trinidad 

 in the British Museum, and this example had been 

 collected by Lord Crawford in 1875 during his 

 first visit to the island. This skin had remained 

 undescribed, owing to the fact that the bills of 

 both forms become totally black in the dried 

 skins, the light blue of the Pacific and Indian 



* " BuUetin Brit. Orn. Club," XVI., p. 102. 



