Royal Society. 253 
^hc animal, they at length were inf^rtcd into the fpine of the 
Os Ilium -^ the two firll of thele niuicks mull ferve for the 
dilatation or opening of this Marjupiiim or pouchy for thefe 
bones are a fulciment or bafis, their articulation not admitting 
of a cor.traflion inwards, or nearer to each other ^ wherefore, 
when the firll and fecond pair of mufcles a6l, they mufl ne- 
ceffarily open or dilate the mouth of the Marfupum or pouch 5 
the third and fourth pair may ferve to extend thefe bones 
outwards; ^q that when this animal hangs by its tail, as it fre- 
quently does, the weight of the Foetus, in this pouch, by this 
means will not prefs fo much upon the internal A^//i:er^; the 
fifth and laft pair, as they may ferve to dilate the capacity of 
the pouch itlelf, fo likewife the better to fufpend its weight, 
when the animal is prom Capite^ and if it gravitates too much, 
they may retradl it upwards, and this the eafier, as pafiing 
over thefe bones like a pulley, their force is more augmented : 
The antagonitl to thefe mufcles is the SphinBer Marfupii, an 
oval feries of flrong flefhy fibres, which ferve to conftringe and 
clofe the orifice of the pouch, which it does fo perfectly, that 
one would think the fiun here was not flit : The Mdrfupium^ or 
pouch itfelf, was a membranous body, not very thick, tho' 
confifting of feveral coats j and it is reducible into the clais of 
the veficular parts of the body 5 which, according to Dr. ^yfon^ 
are partly mufcles, partly glands, and perform both the office 
of motion and fecretion; for the cavity of this pouch was fbme- 
what hairy.; and in leveral places the hairs were obferved to 
be matred together by a yellowHh fubftance, which oufed out 
of the cutane'ous glands J this liquor, difcharged into the 
pouch from the glandulous coat, was flrong-fcented, and had 
more of the peculiar F(Xtor of this animal than any part befides^ 
but after the fkin, together with the pouch, had been kept for 
fome days, and was grown dry, there was fo great an alteration 
in the fmell, that what before was 10 dilagreeable, was now 
become a perfecl perfume, and fmelled altogether like muik; 
this Marfupium had likewife a mufcular coat, befides the 
feveral other mufcles beflowed upon it to give it motion, as 
was already obferved j it had alfo a vaicular coat, being plen- 
tifully irrigated by blood-veffels, efpecially by two large 
branches, that came from the upper part of the l^hora^^ and 
which might be reckoned the Mammaria^ as they are ftiled in 
other animals; this pouch was failened by feveral membranes 
to the mufcles of the Abdomen and the fkin, but fo as to be 
eafily feparated for the mod part with the fingers ; in this 
pouch 
