112 DICTIONARY OF BIRDS 
what is elsewhere said in this book (pages 828, 829). It is doubtless a 
generalized form,! the survival of a very ancient type, whence several 
groups may have sprung ; and, whenever the secret it has to tell shall 
be revealed, a considerable step in the phylogeny of Birds ought to 
follow. Allusion has also been made to the peculiarities of two other 
forms placed with the last among the Alectorides—Hurypyga and Rhino- 
chetus—each being the sole type of a separate Family. It seems that they 
might be brought with the Gruidx, Psophiide (TRUMPETER), and Aramidz 
(LimpKry) into a group or Suborder Grues,—which, with the Fulicariz ? 
of Nitzsch and Mr. Sclater as another Suborder, would constitute an 
Order that might continue to bear the old Linnean name Grallzx. It 
must be borne in mind, however, that some members of both these Sub- 
orders exhibit many points of resemblance to certain other forms that it 
is at present necessary to place in different groups—thus some Rallidx 
to the Gallinx, Grus to Otis, and so forth; and it is as yet doubtful 
whether further investigation may not shew the resemblance to be one 
of affinity, and therefore of taxonomic value, instead of mere analogy, 
and therefore of no worth in that respect. 
We have next to deal with a group nearly as complicated. The true 
Galline are indeed as well marked a section as any to be found; but 
round and near them cluster some forms very troublesome to allocate. 
The strange Opisthocomus (Hoacrzin) is one of these, and what seems to be 
in some degree its arrested development makes its position almost unique.® 
It must for the present at least stand alone, the sole occupant of a single 
Order. Then there are the Hemrpoprs, which have been raised to 
equal rank by Huxley as Turnicomorphe ; but, though no doubt the 
osteological differences between them and the normal Gallinx, pointed 
out by him as well as by the late Prof. Parker, are great, they do not seem 
to be more essential than are found in different members of some other 
Orders, nor to offer an insuperable objection to their being classed under 
the designation Galline. If this be so there will be no necessity for 
removing them from that Order, which may then be portioned into three 
Suborders—Hemipodii standing somewhat apart, and Alectoropodes and 
Peristeropodes, which are more nearly allied—the latter comprehending 
the Megapodiidz (MrcapovEs) and Cracide (CuRAssows), and the former 
consisting of the normal Gallinx, of which it is difficult to justify the 
recognition of more than a single Family, though in that two types of 
structure are discernible. 
The Family of Sanp-Grovuse, Pteroclidx, is perhaps one of the most 
instructive in the whole range of Ornithology. In Huxley’s words 
(Proc. Zool. Soc. 1868, p. 303), they are “completely intermediate between 
1 Cariama is the oldest name for the genus, but being a word of ‘‘ barbarous ” 
origin it was set aside by Illiger and the purists in favour of Dicholophus, under 
which name it is several times mentioned in the present work (cf INDEX, 
page 1066). 
2 This group would contain three families—Rallidw, Heliornithide (the Fin- 
Foots of Eastern India, Africa and South America) and the Mesitid# of Madagascar 
—for which an at least approximate place has been found by M. A. Milne-Edwards 
(Ann. Sc. Nat. ser. 6, vii. No. 6). 
> Mesites, just mentioned, presents a case which may, however, be very similar. 
