YELLOW-BILLED WHITE EGRET. 



469 



inches beyond the tail, and fourteen inches in length. The 

 tibia, tarsus, toes, and claws are black. The plumage white, 

 with a faint yellowish tinge. 



Now the only differences in the above descriptions are in 

 the general size, the colour of the bill, and that of the feet ; 

 but in the measurements of the bill and feet, as will pre- 

 sently be seen, the difference is great ; and while the one 

 has twenty tarsal scutella, the other has only fourteen. 



Egretta Leuce, an American species, is smaller than 

 Egretta alba. The bill is long, stout, compressed, tapering, 

 its dorsal line straight for two-thirds, then slightly declinato- 

 convex. The bill bright yellow, as is the bare space between 

 it and the eye. The occipital feathers are slightly elon- 

 gated. The dorsal plumes have very slender, slightly de- 

 curved, and slightly undulated shafts, the longest extending 

 about ten inches beyond the end of the tail. The tibia, 

 tarsus, toes, and claws black. The plumage white. 



Some of the measurements of three individuals of these 

 three species are here given : — 



Nigrirostris 



Length 44 6 



Extent of wings . . 66 

 Bill along the ridge 4 9 



Gape-line 6 2 



Height of bill 101 



Wing from flexure .18 3 



Tail 7 



Bare part of tibia . . 5 6 



Tarsus 7 9 



Third toe 4 6 



Its claw 8 



Alba. 

 40 



4 7i 



101 



16 



6 6 



3 8 



6 5 



3 6 



7^ 



Leuce. 

 37 

 55 



4 7 



5 5 

 11 



16 6 



6 3 

 3 6 

 6 1 

 3 11 

 9 



It will be seen how greatly Egretta nigrirostris exceeds the 

 others in the bare space on the tibia, in the tarsus, and in 

 the middle toe. All the individuals described were adult, 

 with the dorsal plumes in the same state. 



It is clear that Egretta nigrirostris exceeds Egretta alba 

 in size, as much as the latter exceeds Egretta Leuce. Its 

 bill, however, is more slender than that of either, and its 



