Chap. j. 
RUDIMENTS. 
23 
10 e external ear being permanently pressed back- 
, au S- many monkeys, which do not stand high in 
16 01 ^ Gr » as baboons and some species of macaeus, 25 the 
l Ppei portion of the ear is slightly pointed, and the 
Margin j s not at all folded inwards ; but if the margin 
"'ere to be thus folded, a slight point would necessarily 
Project inwards and probably a little outwards. This 
con hi actually be observed in a specimen of the A ides 
eelzebuth in the Zoological Gardens ; and we may safely 
conclude that it is a similar structure — a vestige of 
^oirnerly pointed ears — which occasionally reappears in 
^> e nictitating membrane, or third eyelid, with its 
nccessory muscles and other structures, is especially 
VVe developed in birds, and is ol much functional im- 
portance to them, as it can be rapidly drawn across the 
" o e eye-ball. It is found in some reptiles and arnphi- 
an d in certain fishes, as in sharks. It is fairly 
e developed in the two lower divisions of the mam- 
noi ian series, namely, in the monotremata and marsu- 
1 la s, and in some few of the higher mammals, as in the 
' a rus ‘ '’Of in man, the quadrumana, and most other 
lammals, it exists, as is admitted by all anatomists, as 
a rue re rudiment, called the semilunar fold. 20 
the 16 S6nSe SIII< dl is of the highest importance to 
greater number of mammals — to some, as the rumi- 
nants, in warning them of danger ; to others, as the 
23 
roidea m S ° me remal 'ks, and the drawings of the ears of the Lemu- 
ZooW ‘ easrs - Murie and Mivart’s excellent paper in 1 Transact. 
26 MuilerW,” 1 18G9 ’ rp ' G and 90 ‘ 
1117. 0 ^lements of Physiology,’ Eng. translat., 1842, vol. ii. p. 
Walrus ‘p, ■U natori:| y of Vertebrates,’ vol. iii. p. 2<J0; ibid. on the 
' Great Artist-' Soc -’ November 8th, 1854. See also E. Knox, 
wrnewhat lar* aUd .' , ^ na ^ om ^ s ^ s ’' P- 10G. This rudiment apparently is 
V °gt, ‘ I m q c S roes and Australians than in Europeans, see Carl 
es 011 Man,’ Eng. translat. p. 129. 
