94 Proceedings of the Biological Society of Washington. 



coverts dull greyish white; dorsal plumes pale grey, the longer lateral 

 ones slightly greenish toward tips and edged hasally with buffy; lower 

 back, rump, upper tail coverts and tail dull grey; each rectrix bordered 

 all round with white, the outer ones mostly white; remiges dull slate 

 grey, each feather narrowly edged with white and white-tipped, except 

 the four longest — outer most — primaries, on which the white tips are 

 nearly obsolete; all the other wing feathers very deeply margined with 

 whitish, becoming pale buffy on some of the middle and most of the 

 lesser coverts. 



Measurements. — Type, adult female, wing, 165 mm.; tail (feathers), 57 

 mm.; exposed culmen, 63 mm. ; tarsus, 46 mm. 



Remarks. — So far as general paleness of coloration is concerned the 

 Green Heron of the Maldives is, without doubt, most nearly matched by 

 Butorides crawfordi Nicoll of Assumption Island, and both species present 

 the striking character of the tail feathers, all being deeply bordered with 

 white. The latter species was probably, however, derived from Butorides 

 atricapillus (Afzel.), whereas Butorides albidulus of the Maldives had its 

 origin in Butorides javanicus. (Horsf. ), and the general likeness of the 

 two species is probably due to their both living under similar conditions 

 upon coral islands, and not to near relationship. 



The new bird differs from B. crawfordi* chiefly as follows: Crown 

 green (not blue); underparts mostly pale grey, not (wholly "milky 

 white"); no series of dusky spots along front neck; tail and upper tail 

 coverts as well as rump grey (not green); wings with much wider pale 

 borders to the feathers, these borders white on primaries and secondaries, 

 buff on most of the smaller feathers. 



•I of course have seen no skins of B. crawfordi and base what I say upon the 

 description, Bull. B. O. C. Vol. XVI, p. 105, 1906, and the plate, Ibis, 1906. 



