404 
condition was only manifested in the females 
with ovaria, large indeed, but without promi- 
nent ovisacs, and in which the recent corpora 
lutea were almost absorbed. These facts were 
established by the dissection of five female 
Ornithorhynchi. 
In each of these specimens the mammary 
gland was composed of between one hun- 
dred and two hundred elongated subcylin- 
drical lobes, forming an oblong flattened mass, 
and converging to a small oval areola in the 
abdominal integument, which areola is situated 
between three and four inches from the cloaca, 
and about one inch from the mesial line. The 
lobes in the fully developed glands are rounded 
and enlarged at their free extremities, and 
measured at that end three or four lines in 
breadth, and became narrower to about one-third 
from the point of insertion, where they end in 
slender ducts. Almost all the lobes are situated 
at the outer side of the areola, and remark mand 
converge towards the mesial line of the abdomen. 
Between the gland and the integument the 
panniculus carnosus (fig. 199, a) is interposed, 
closely adhering to the latter, but connected 
with thegland byloose cellular membrane. This 
muscle is here a line in thickness, its fibres are 
longitudinal, and, separating, leave an elliptical 
space for the passage of the ducts of the gland 
to the areola. On the external surface of the 
skin, when the hair is removed, this areola can 
ouly be distinguished by the larger size of the 
orifices of the lacteal ducts, compared with 
those for the transmission of the hairs. 
Mammary areola, Ornithorhynchus, natural size. 
(Owen, Phil. Trans. 1832.) 
The orifices of the ducts thus grouped together 
form an oval spot, which in the female with 
the largest glands measured five lines in the long 
and three in the short diameter. In none of 
the specimens was the surface on which the 
ducts terminated raised in the slightest degree 
beyond the level of the surrounding integument. 
eckel was disposed to believe that the 
ducts terminated on a small eminence about 
the size of a millet-seed, but did not succeed in 
demonstrating the fact by injection of the ducts.* 
* Meckel writes: ‘* Ductuli excretorii, maxime 
attenuati, in glandul# medio extrorsum aperiuntur. 
Quamvis neque setas, neque mercuriam per ductus,et 
per se, ut monui, angustissimos, et spiritu vini con- 
MONOTREMATA. 
Not any of the specimens of Ornithorh 
chus examined by me have presented a 
mammary eminence of any dimensions; on 
the contrary, I have succeeded in demonstrat- 
ing the termination of the lacteal duets on 
the flat areolar tract. Having in vain at- 
tempted to insert the smallest absorbent 
pipe into the mouths of these ducts, I thrust 
it into the extremity of one of the elongated 
lobes, and after a few unsuccessful efforts 
at length saw the mercury diffuse itself in mi- 
nute globules through the parenchyma of the 
lobe, and at a distance of an inch it had evi- 
dently entered a central duct, down which it 
freely ran to the areola, where it escaped exter- 
nally from one of the minute oritices just de- 
scribed. This was re on most 
of the lobes with similar results, the greater 
part of them terminated by a ange duct open- 
ing exteriorly and distinct from the rest, but in 
a few instances the ducts of two contiguous 
lobules united into one, and in these cases the 
mercury returned by the anastomosing duct 
and penetrated the substance of the other lobe 
as pi! as that into which the pipe had been 
inserted. 
Some of the lobes injected by the reflux of 
the mercury through the duct, and of which it 
was more certain that the glandular structure 
and not the cellular membrane was filled, were 
dried, and various sections were submitted to 
microscopical examination. At the greater 
extremity they are minutely cellular, the cells 
communicating with each other, and elongating 
as the lobule grows narrower, first at the centre, 
so as to form apparently minute tortuous tubes, 
which tend towards and terminate in a 
central canal, or receptacle, from which the ex- 
cretory duct is continued. On making a sec- 
tion of the corium through the middle of the 
areola the ducts are seen to converge sli 
to the external surface, but there is no inve 
or concealed nipple at this part, as in the Kan- 
garoo. ( Fig. 201 is a sketch of a magnified 
view of this section, with the section of one of 
the dried and injected lobules.) 2 
Thus, prior to and independently of any { 
direct observation of the secretion of theab- 
dominal glands, the anatomical facts f 
to bear upon their disputed function were in- 
dubitably more favourable to the opinion of — 
the German than of the French Drotensont 
for, 1st, the glands are confined to the 
and vary in degree of development at 
ferent periods in individuals of equal size, at- 
taining in some an enormous development; — 
2nd, the secretion is conveyed ow | 
means of numerous long and narrow ducts, — 
4 
4 
tractos, et fluido concreto repletos,trajicere nD, 
area tamen indicatur in cute. Quamvis pili hat par- 
tem tegant, apparet tamen, hos si abstuleris, plaga 
uinqgue circiter lineas longa, tres lata, foram : 
iis, e quibus pili egrediuntur, majoribus, nigris, 
circiter octoginta stipata, forsan ductuam excre- 
torium orificiis. Praterea in hujus medio j 
siancula duarum linearum diametri adest, . 
destituta, sed eminentiunculis inaequalis, inter quas- 
precipne una, milii granum haud aquans, reliqu 
antecellit. Hz sine dubio papille et dactuum ori- 
ficia sunt,” —Loc. cit. p. 54. ‘Cas 
