C 844 ) 
AlUntois Cif it is not the Chorion') is fome Coat accider> 
tally formed, irotn a Rednplication of the Membranes : 
becaufe ( fince every Membrare is double ) Naiure itiay 
upon a ftreight, lodge the Urine between a D//;j//V^///m 
Yet hedoes not tell us how Dnplicature is to be filled, 
he allowing no Vrachus, But , in (hort, this Vrinary 
Bladder, can be no Duplicature ot the other Membranes, 
fince iii^ all Animals it differs from them, as to Figure, 
Texture, and in having an which v no other 
Membrane has. And fince every Anitiial that has a 
Bladder, muft have a like neceflity for Receptacle of 
Urinctill born^fince alfo the ZJr^fi^ is ever alike inferted 
in the {dm^ Sfedes of Animals, - and the Urinary Bladder 
conftantly the fame, "as toShape, Texture, Situation, &c. 
(^yn^^y^ih^ Vrachis^ndi AI/ar4ok with hs (g) By-Watcr can be 
Hum. no accidental or preternatural things. 
All the material Objeftions, and Difficulties about an 
'Hi4?^ane AUa^ttokhdx)^ thus clearedj I fliall now confider 
what has been, or may be, offered againft xhtk Figures 
in particular/ when I have firft given the Explication of 
them. And i think there is no need of any other account 
thereof, fince 'tis notmy defign to give an entire Hiftory 
oi the Scchnd'hes^ &c. or repeat what can be found m 
other Anatomifis 5 but only to relate what I have difco- 
vered of an Humane AUantok^ Amnios^ d^c, which is al» 
together new, or different from the Obfervations o£ 
others, . 
Fig, L 
Reprefents the Secnn dines of Twins, to (hew the Allans 
^ iois, and its Relation to the other Membranes^ &c. after 
the pans were prepared ard dryed. 
A A A A Part of the C^i?m// expanded. - 
B B B a Line, expreffing the edges of the placenta. 
C C C the Amnios, which is united, fa > 
iy..\h(^AHantok^2it 
E^E.E the Line of 
' F-^/th©...,.., 
