HETEROMERI—HOACTZIN 421 
xanthochroism ; while blue, in the absence of the colour-producing 
surface, may appear brownish or grey. The pale coloration of 
“ Desert-forms” (supra, p. 336), and the seasonal and sexual changes 
of colour in many species, though perhaps ultimately referable to 
acts of Heterochrosis, are not covered by this term since they are 
now become normal features (see COLOUR, p. 99). 
HETEROMERI, Garrod’s name (Proc. Zool. Soc. 1876, pp. 517, 
518) for a group composed of Cotingidx (CHATTERER) and Pipridx 
(MANAKIN) which differ from most other birds in having the 
femoral artery developed instead of the sciatic, wherein they are 
opposed to the Homa@omeri, but both combined form his 
MESOMYODI. 
HETEROMORPH, Prof. Huxley’s name (Proc. Zool. Soc. 
1868, p. 311) for an ornithological section consisting, so far as 
known, of a single genus, Opisthocomus (HOACTZIN). 
HEWEL,? HEWHOLE, HICKWALL and HIGH-HOLDER, 
names given in various places to a WOODPECKER of one kind or 
another. The first two are said to be corrupted from the third,” 
the older form of which, ‘ Hickwaw” (Hollyband) and “ Hickway,” 
“ Heigh-hawe” and “ Highawe” (Cotgrave), can hardly have come 
from anything but the Anglo-Saxon Higera or Higere (T. Wright’s 
Vocabularies, pp. 29, 62, 281) meaning a laugher, and doubtless 
referring to the cry of the Green Woodpecker, Gecinus viridis. 
Hewhole was, however, in use in 1544, as shewn by Turner, who 
Latinized it Huhola ; and in North America it has taken the further 
modifications of High-hole and High-holder for the FLICKER 
(Audubon, Orn. Biogr. i. p. 191; Ingersoll, Bull. Nuttall Club, 1881, 
p- 184). For further information on these and other English 
synonyms of Woodpecker see Yarrell (Br. B. ed. 4, ii. pp. 461-463).? 
HOACTZIN or HOATZIN, a bird of tropical South America, 
thought by Buffon to be that indicated by Hernandez under these 
names, the Opisthocomus hoazin or O. cristatus of modern ornitho- 
logists—a very curious and remarkable form, which has long 
exercised the ingenuity of classifiers. Placed by Buffon among his 
“« Hoccos ” (CURASSOW), and then by P. L. 8. Miiller and Gmelin in 
1 For this Andrew Marvell on (Nun) Appleton House (lines 557 e¢ seqg.) may 
be cited. 
2 If Hewhole be a corruption of Hickwall it has been obviously brought in by 
the bird’s habits ; but we must not forget that Wolzhawer is a German equivalent 
(Bechstein, Gemeinn. Naturgesch. Deutschi. ii. p. 1007). 
3 The derivations of the many names of the Woodpecker in the earlier 
editions of Yarrell’s work are extremely erroneous, being the werk of some 
anonymous authority in days before the study of words was placed on a sure 
basis. 
