( >58o ) 
j^rtcries to drive up the Blood in the Veins towards the 
Heart 3 but that contrivance feems no way neceflary in 
this Animal, becaufe the contrary pofition of its Body is 
'more cuftomary in hanging by its Tail with its Head 
downwards : It is not unlikely, if the Veins of this Ani- 
mal were examined below the Heart (which indeed I did 
not think of till thofe Parts were thrown away ) but we 
fhould meet with fome Contrivance to prevent the Preci- 
pitate Flux of the Bloud in that Pendulous Pofition, as I 
have fobferv'd in the Trunk of the Cava immediately 
above the Liver in Dogs. But to return to the Sperma- 
tick Veflels. 
The Arteries a a arife from the forepart of the De- 
^ fcending Trunk of the Great Artery, and pafs through a 
^"^^' very fmall Perforation ♦ made on purpofe in the 
Vefia Cava, and defeend ftraight to the Tefies^ as in Hu- 
man Bodies, and are not contorted in their progrefs, as 
we find them in moft , if not all Quadrupeds, This 
Perforation of the Cava perhaps was not only made for 
tranfmitting theSpermatick Arteries, but may alfo frame 
an Amlus^ that may check the velocity the Bloud would 
otherwife have in thofe Arteries, which rapid Motion of 
the Bloud we find Nature ftudioufly avoids in the Te(les of 
all Animals : For in Men we fee thefe Spermatick Arteries 
(contrary to all other Trunks of Arteries) are lefs at their 
Originations from the Great Artery 5 and in Quadrupeds 
(except in this ) the Spermatick Arteries are contorted 
(^)PhiL before they reach the Tefles^ as I have (^) elfewhere 
Traiii; taken notice. The Spermatick Veins, after leaving the 
v^^ii^oT^f^^^ of this Animal (like thofe of Humane Bodies) have 
feveral Divifions and Inofculations, which are all re- 
duced to one Trunk on each fide, and empty therafelves 
fif>. 2. ^^^^ immediately above the Perforation b b. 
Had the known Strufture of the Teftes^ in relation 
^ to their Excretory duds been left undifcovered till now, 
the bare infpeftion of thofe parts in this Animal would 
inftruft 
