JRII IN T K O D T J C T I O N . '
The BtJOEiioTiB« appear to me susceptible of arrangement into two divisions or subfamilies,
containing the GUOOTD- and TNEI-nornbiUs respeetiycly. Of the fii-st of these we have at the
present day three species, ivhich possibly are the sole remaining members of what may have been
an extensive group, and diifer from the rest of the famfly in many particulars, the most
conspicuous of which are the long legs formed for walking, whereas all the other spccies have short
legs and can only hop. llyologieaUy, also, these hu-ds diifer from the rest of the BTiCEEOTmiE in
having only two muscles of the thigh represented, viz. the semitcndinosus and the accessory
semitendinosus; while the ambiens, the femoro-caudal, and the accessory femoro-caudal are
absent. In the genera BTioiiiios and ToCKns the accessory fcmoro-caudal muscle is present.
Por «lis subfamily I would propose the term Bucoimsj!. The other, BtJCDaoiisiE, contams
the remaining spccies, amounting to over fifty in number, comprising various groups allied to
eaeh other in the form of their easqne and general colour of plumage; and in many of thorn their
natural afllnities are further upheld by their geographical distribution. The genera for these
various forms have been many, all authors seeming to appreciate the difBeulty of retaining these
birds in one or two genera, as the older writers did. Of the thirty-four genera proposed, I have
employed nineteen, which, I consider, fairly represent the different forms existing at the
present day. The single genus Tochm is made to contain perhaps some spccies which might bo
deemed at least subgenerically different from the typical style ; but I do not think it essential to
make any such divisions, as in the main the species are all really members of one genus, the
more or less sUght elevation of the enlmon being about the only character which eould be
urged in behalf of a separation of the species.
I commcnee the airangement of the family with the genus BUOOBVUS, containing three
speeics. These birds have many eharaetcristies to separate them from the other members of
BUCEKOTIDJ!. They are essentially ground-birds, yet ascend to the branches of trees; but their
home is the ground, over which they walk with case, while their relatives arc tree-loving birds,
descending but rarely to the earth, upon which they move by awkwai-d hops. Here at once is
pcreeived a gi-eat difference of habit; and to aecommodatc tho Ground-Hornbills to their different
life, thch- anatomical structure is modified. The second subfamily, BuciiEOTiSiE, contains the
greater part of the family; and these all live in and among the trees. I begin with tho genus
BUCEBOS as containing a typical form of the true HornbiU, with two species, the chief (and perhaps
only) difference between them being the upturned casque of the one, and the straight casque of the
other. The third genus, DicnoOEUos, was formed for the weU-known Ucomis, the anterior corner
of whose horns turns slightly upward. Next to this, as belonging to the flat-casque group,
I place the genus HTOEOCOEAX, with three species; to be followed by Knixopl ix, contammg
the extraordinary bird with solid easqne, bare neck, and elongated median reetrices. Between
all these genera gaps exist, which at the present time we are unable to fill; but we may feci
assured that the extinct species w^hieh once supplied the desiderata were no less wonderful m
sti-ueture than are their relatives which remain with us. ASTHEAOOCEEOS now mtroduees the
species bearing an upright, more or less lengthened, laterally compressed casque. It contains
five speeics, possessing, for the size of the bh-ds, quite large casques, highest anteriorly. Four
INTKOBtJOTION.
of the spccies resemble eaeh other closely in appearance, both as to casque and plumage; but
the fifth has a perfectly white casque and a conspicuous superciliary stripe, not observed in tho
others The seventh genus is OEAKOEEHlNtis, with four speeics, distinguished by high, upright,
keel-shaped casques extending half the length of the bill, with several undulations on the sides;
and this genus is followed by PuiiEiopinES with three speeics, of much smaller size, lower
casques, and grooved bills. The birds of tho last three genera, although they do not follow eaeh
other in regular order, unknown forms being required to supply tho void between each two
genera, still are closely related, and seem to constitute a natural group in the family. I now come
to birds also possessing high and largely developed casques, but which are natives ot a different
zoogeographieal region, and, as might be supposed, are rather widely separated from tho members
of the previous genera, yet at the same time possess eharacters in common with them. Several
links are needed here to complete the lino between tho last-named genus and OEEATOGYMNA,
the one I now reach. This has but a single species, though one that is very remarkable for tho
form of its casque, whieh is large, bulky, extending over half the maxilla, rather flattened on its
anterior face, which is upright; large irregular grooves also run along the sides of the casque
near the maxilla. Allied to this is the single species of tho genus SPHAGOIGEDS, but with a
casque differently shaped and even larger than the other. Pollowing this I place the genus
LMOXOPNALES with a single species, suceecdcd by BYOANISTES with six species, having, as a
rule, a casquc longer than the bill, pointed anteriorly, and curving to the eulmon. iSIext is tho
genus I'noLiDOPEALns with three species without a casque, but with a roughened casque-like
protuberance eoyering the basal thu-d of the oulmen. These last five genera with their species
form a well-marked group, with similarly coloured plumage; but, like the others, tho links are
wanting by whieh the existing species could be more readily arranged. Through the speeics of
tho last genus we are led to those birds whieh have bUls devoid of casqucs, or else tho latter
represented by flattened protuberanees having the appearanee of bony scales. These are contained
in the genus RETTIDOCEEOS, and consist of four species, one of which, like the members of the
last genus, has transverse grooves at base of bill. The species of the fourteenth genus do not
possess casques; but, in lieu of this appendage, the oulmen is eompressed laterally, and elevated
into a low crest descending gradually forward to the oulmen. There are five species included in
this genus (ANOEEHINUS), aU having long loose erests on the head and occiput. ACEEOS, the next
genus, contains but one though a large and fine speeics, without casquc, the culmen swollen at
the base of maxilla. With this bird the list of the large Hornbills is finished, those that remain
decreasing in size until we arrive at the last one, no larger than a day. Exarlmta, which is
the sole species of the genus HYDEOCISSA, has really no ally in the family, and is remarkable
for its erest-like casque, hardly to he distinguished from the maxilla, and is moreover peculiar
for the lateral grooves running its entire length. It is a Celebes form, and probably is the
sole sm-vivor of a subgroup of this famfly. LopnocEEOs, the next genus, contains but two
speeics, allied closely to the members of the succeeding one, but differs in having the low casque
extended to a point at its anterior end, returning to the culmen by an acute angle. The last
genus into which I have divided the family is TOCKUS, containing twelve species. Some of these