588 MR. F, E. BEDDARD ON THE [Dee. 3, 
been dissected by me); and in addition one liver-lobe—the right—is 
commonly separated from the abdomen by a thin membranous 
septum. In Hornbills both lobes of the liver are thus shut off; I 
have figured this condition in Bucorvus abyssinicus* ; it is exactly 
the same in one or two other species which I have subsequently 
studied. This condition is, so far as my experience goes, rare in 
birds ; since, however, I propose later to bring forward some facts 
relative to: the arrangement of the viscera and the partition of the 
ccelom in birds, I only dwell upon this character now as tending to 
separate the Bucerotidee from most of their allies. 
Syring. 
Aceros nipalensis—The last rings of the trachea are fused 
together to form a solid box, at the sides of which, however, the 
individual rings are recognizable. In front the last three rings are 
thus fused, but behind two additional rings fuse with the others to 
form a wide and deep bony plate. The tracheal rings lying in front 
of these five show the dovetailing arrangement which is so often found 
in the tracheal rings. The pessulus is well developed and bony, but 
owing to the complete fusion of the tracheal rings both posteriorly 
and anteriorly it is impossible to say from which rings it is de- 
veloped. 
The intrinsic muscles of the syrinx are attached near to the 
boundary-line between the last and the penultimate tracheal rings. 
The bronchial semirings are cartilaginous, and there is a consider- 
able interval between the first of these and the last tracheal ring, 
Bucorvus abyssinicus.—Vhe syrinx of this Hornbill (fig. 1, p. 589) 
differs in many particulars from the last. The tracheal rings are not 
ossified, and there is no box formed by their fusion. Only posteriorly 
are the penultimate ring and the two in front of this fused just at the 
origin of the pessulus; anteriorly the pessulus is fused with the 
antepenultimate tracheal ring, which forms with it a three-way 
piece; the last two tracheal rings do not meet in front. The 
slender syringeal muscles are attached to the anterior margin of 
the last tracheal ring. 
The peculiar shaped tracheal rings are hardly recognizable until 
about the 14th from the end. 
Buceros rhinoceros (fig. 2, p. 589) has a syrinx which is not very 
different from that of Aceros. The same rings are fused to form 
an ossified box; but the fusion between the several rings is hardly 
so extensive as in Aceros; furthermore the syringeal muscles are 
attached to the posterior border of the last tracheal ring. 
In Sphagolobus atratus there is very little fusion between any of 
the last tracheal rings ; the last three rings, which alone show any 
signs of ossification, are fused for a very short space anteriorly ; 
posteriorly there is no fusion at all, and the pessulus can be plainly 
1 “Notes on the Visceral Anatomy of Birds.—I. On the so-called Omentum,” 
P. Z. 8. 1885, p. 842, woodcut, fig. 2, L. 
