THE ISLANDS OF THE BAY OF BENGAL. 305 



speak hereafter, be separated as a distinct bird, but it is 

 quite clear with the very large series that we now possess of the 

 ashy bird, that all those inhabiting the islands of the Bay of 

 Beno-al and its Eastern Coast belong to one and the same 

 species. 



The following is a resume of the measurements of the insular 

 bird. There appears to be no constant difference in the size of 

 the sexes, though the birds vary very greatly in size according 

 to age, especially where the length of bill is concerned : — ■ 



Length, 21 to 24 ; expanse, 36*5 to 40*75 ; wing, 9-85 to 

 11*75; tail, from vent, 3 to 4*25; tarsus, 2'7 to 3*1 ; bare 

 portion of tibia, 1*05 to 1*5 ; bill, at front, 2*65 to 3*5. 



Variable as these dimensions are, every tenth of an inch 

 between the extremes is represented in one or more specimens, 

 so that it is absolutely impossible to separate the larger and 

 the smaller, as Von Pelzeln, with only a limited series before 

 him, has been led to do. 



The color of the soft parts is excessively variable. In 

 the adult the bare portion of the tibia varies from dark 

 grass green to greenish plumbeous ; the back and sides of 

 the tarsus and the greater part of the toes are generally 

 pea green, sometimes duller, sometimes yellower ; the front 

 of the tarsus and the first joint of the mid toe black, but 

 sometimes these parts are green, only patched or mottled 

 with black, and sometimes the black extends along the ridges 

 of all the toes ; the bill and bare skin in front of the eye vary from 

 sienna brown to chocolate ; sometimes the bill is a sort of light 

 mahogany color, and the bare skin a sort of greenish brown ; 

 usually the bills are yellowish at the tips ; the lower mandible 

 is generally lighter, sometimes brownish horny, sometimes yellow- 

 ish horny ; and in the breeding plumage the whole lower man- 

 dible becomes apparently a very decided, though dull, yellow ; 

 the irides vary from bright to deep yellow. I suspect, though 

 we have not been able to work it out, that these differences 

 in color are due both to age and to season. 



The adult in full breeding plumage is everywhere of a 

 deep blackish slate color ; the feathers of the head almost 

 black ; the feathers of the upper breast greatly elongated, 

 as are those of the middle back, some of the latter disin- 

 tegrated ; the elongated feathers of a paler slatey grey, those 

 of the breast not exceeding 3*5 inches in length, those of 

 the back reaching quite to the end of the middle tail 

 feathers. In most specimens there is a somewhat brownish 

 ashy tinge on the abdomen and vent feathers. In some 



