( 845^ ) 
moftof thefe upon C^?) Difleftion were found to have P^^-^y 
hut o^e Hearty one Ltve}\ £<c. whence 'lis molt plain, Lib. 25. 
that thefe Mo^fiers (md no doubc all others J were origi- 
m\\Y Monfiers \n ihQ Ovd^ before Impregnation, and not^^^ ^^;^^ 
fo from want of an the Amnios. Yet ("p) Diemtrbroeck does Libixap, 
not a little boaft of having fiift f as he thinks), found the 3<^-and3i' 
reatoo why Twins rauft Ire in diftid Amnios s. But ilace 
the matter of fa6t(fometime3 'at leaft as in thefe Secnndwes^\ 
where there was only one i4.^;;?i?j%and two regular F^r/^;//) 
is not true, his argument for a neceffity of two Ammos's- 
for two Fmtfiss^ will never prove valid, even where 
Twitjs^ and two Ammo/s are found. Indeed any part may- 
be made to grow to any part, as we fee in the cure cb 
Hdir lips^ &Lc, but then the Fibres muft he ^firft broke^^ 
before there can be any Umon. Now I can't conceive 
vv hat fhould naturally break the Fibres of the Tmns in ■ 
the ZJiems. Bat alrhough 'tis evident from what has 
been (aid, that Iwws may lie diftinCt in the fame Ammos^ 
yet there muft be as many Urachuss^ as Foetus s. In 
thefe Scciindims I faw two running over the FiacefJta^ to 
the Nec^ of the Allantois^ which T communicated to 
fome Phyficians, before the parts began to grow dry. 
The Urachuf palTes under the Amnios as the other Urn- 
hiUcal Vejfels do, and runs from that part where the 
TJ^bilicd Rope is fet on to the Placenta^ ftraight to the 
Cervix F. S defcribes the courfe of th^iUrachus marked R 
at F in the 2d The other Urachus lay about a 
quarterof an Inch laterally beyond that marked R in the 
fame Figure. I mean by two Vrachuss^ two long round- 
ifh Bodies, of a depreffed Figure, they feemed.as big as a 
common Knitting Needle, and were of a darker fub- 
ftancc than the Placenta on^ which they lay. They 
appeared in every refpeft like that part of the Navel- 
firing which is allowed by all Anatomifts to be the 
Urachus^ and in like manner fhrunkin two or three days, 
from a. Mucous fubfkance to a meer Membrane. 
Thefe - 
