Fig. 201. 
hi twice natural size. 
_ strongly implying its fluid nature, and most 
_ Contrary to the mode in which odorous sub- 
_Stances are excreted; 3rd, the excretory ori- 
fices are by no means extended over so wide a 
_ Space, in proportion, as in the Shrew, but col- 
lected into a point which we know to be not 
_ disproportionate to the size of the mouth of the 
_ young animal, and this point is situated in a 
_ part of the body convenient for the transmission 
_ of a lacteal secretion from the mother to her 
Be ve with an ordinary mammary gland 
that of the Gidithorhynchus differs chiefly in 
_ the absence of the nipple, and, consequently, of 
_ the surrounding vascular structure necessa 
for its erection. But the remarkable modifica- 
____ tion of the mouth in the young Ornithorhynchus 
_ Temoves much of the difficulty which previously 
attached itself to the idea of the possibility of 
an animal with a beak obtaining its nutriment 
_ bysuction. The width of the mouth in the 
_ smallest observed Ornithorhynchus — corres- 
~ 
MONOTREMATA. 
Terminal ducts, and lobe of mammary gland, injected ; 
405 
ponds with the size of the mammary areola; 
and the broad tongue, extending to the apices 
of the broad, short, and soft jaws, with the 
fold of integument continued across the angle 
of the mouth, are all modifications which pre- 
pare us to admit such a co-adaptation of the 
mouth of the young to the mammary outlet of 
the parent, as, with the combined actions of 
suction in the recipient, and compression of 
the gland in the expellent, to effect this essen- 
tially Mammalian mode of nourishment. 
We may presume that a corresponding mo- 
dification of the mouth of the new-born 
animal obtains in the Echidna, since the mam- 
mary glands in this Monotreme* correspond in 
structure, and mode of termination of the excre- 
tory ducts, with those of the Ornithorhynchus, 
As yet the secretion of the mammary glands 
of the Echidna has not been observed ; but that 
of the Ornithorhynchus has been detected not 
only in the stomach of the young (unfe p.401), 
but oozing from the lacteal pores of the female, 
and by more than one competent observer.+ 
Mr. George Bennett, describing his dissection 
of a female Ornithorbynchus shot at Mun- 
doona, New South Wales, on the 14th 
of November, the day before his arrival at 
that place, and which “ had evidently just 
produced her young,” and had very large 
mammary glands, thus records his obser- 
vation of their secretion. “The glands were 
very vascular on the surface, the mammary 
artery ramifying over them in a most beautiful 
and distinct manner. The fur still covered 
that portion of the integument on which the 
ducts terminated, and there was no appear- 
ance of a projecting nipple.” “ How different 
was the appearance in the recent state of this 
mammary gland from that which I had pre- 
viously seen at the Royal College of Sur- 
/ geons, in a specimen long preserved in spirits, 
in which I had the opportunity of witnessing 
the injection of the ducts with mercury by my 
friend Mr. Owen, the mercury exuding, as I 
have seen the milk from the similar ducts, 
upon the integuments.”—Zoological Trans- 
actions, vol. i. p. 251. In a female Ornitho- 
rhynchus, which with her two full-furred young 
were captured alive by Mr. Bennett on the 
28th of December, he says, “ The milk that 
could be expressed from the glands was but 
trifling in quantity; and, in the mother of these 
young animals, such would have been expected 
to be the case, for they were capable of feeding 
upon more substantial diet.” —Ibid. p. 254. 
Crural gland and spur.{—This remarkable 
* See Phil. Trans. 1832, p. 537, pl. xvii., figs. 
2 and 3. 
+ Hon. Lauderdale Maule, Proc. Zool. Society, 
0 ii. p. 145. G, Bennett, Esq. ib. part i. p. 82. 
art ii. p. 141-11. 
$ Meckel, loc. cit. p. 54, calls this peculiar 
sexual gland ‘ femoral,’ observing, ‘‘ ne ipso no-= 
mine de functione judicium proferam, forsan re« 
trahendam, hoc nomen 4 situ impono.” As, how- 
ever, the femoral position is peculiar to the Orni- 
thorhynchus, the gland being popliteal in the Echid- 
na, I prefer a name derived from the word ‘ crus, 
which has a more extended signification to the 
whole hinder extremity. : 
