50 VISCOUNT WALDEN ON THE BIRDS OF CELEBES. 
of lateral folds. But the position which is occupied by the lateral plates in older 
individuals is indicated by a dingy reddish brown colour. 
In the next stage (fig. 2, p. 48) the bill measures about one inch longer, and has 
acquired the form which exists in the old bird; but the cutting-edges are unbroken. 
The casque is more inflated, appears more detached from the culmen, and reaches 
further back on the crown of the head. In front it stands up ata right angle to the 
culmen, and is much compressed. A thin, smooth plate has grown on the basal half of 
the two mandibles; but there are no traces of folds or grooves. The substance of these 
plates seems to be secreted from the walls of the mandibles. 
In the fully adult bird (fig. 3, p. 49) the commissure is serrated, notched, and broken. 
The casque extends back past the line of the eye. Anteriorly it is less compressed 
than in the previous stages, although not so much swollen as the posterior portion. The 
anterior edge stands at an acute angle to the culmen. ‘The casque displays five distinct 
folds or, rather, undulations. At the base of the mandibles the lateral plates are much 
thickened. On each side of the maxilla they are divided by a single, deep, diagonal 
groove into two equally broad flat folds. On the sides of the mandible there are two 
grooves thus forming three similar folds. 
In the adult female (fig. 4, p. 49) the commissures are much broken and serrated. 
The casque is smaller, the anterior edge rising at a right angle to the culmen. It is 
also divided into five almost equal undulations or folds. The basal plates are divided 
both on the mandibula and maxilla into three broad flat bands. In a second example 
of a female (mus. nostr.) a third band has been partially arrested in its development, the 
groove being being partly obliterated. While the female has certainly three flat bands 
at the base of both the mandibles, it will be interesting to know whether the male has 
never more than two at the base of the maxilla. In Temminck’s plate (/. ¢.) the male 
is figured with only two; while in that given by Schlegel and S. Miiller (/. ¢.) the 
female is figured with three both above and below. ‘The following dimensions are 
taken from Menado examples in my collection. The bill is measured in a straight line 
from the gape to the apex. 
Dimensions. 
Wing. Tail. Bill. Circumference of casque. Casque. 
Outer. Inner, Height. 
inches. inches, inches, inches. inches. inches. 
Male, young .......... 163 113 62 53 4 13 
Male, intermediate...... 173 14 7 53 3 23 
Mialeadult:..<: sist aleacece 17% 14 8 Tz 3g 3g 
Female, adult.......... 15 12 i 5 37 2 
It will be seen that the bill increases in length after the wings and tail have reached 
their maximum. The inner circumference of the casque is greater in the youngest 
than in the adult. The anterior part of the casque, at its union with the culmen, 
