12 Macieay Memoria Vouume. 
(1) Zac artery.—This is a comparatively small vessel running downwards, 
outwards and backwards to supply the hind limb (figs. 10 and 14, 2 z@ac art.). 
(2) Posterior spermatic (or oviducal) artery.—This runs at first downwards and 
then turns forwards, passing through the anterior part of the kidney to supply the 
testis (or ovary) along which it runs, and, as stated above, is directly continuous with 
the anterior spermatic (or oviducal) artery (figs. 10 and 14, 2 fost. sperm. art.). 
(3) Renal artery.—This runs downwards and backwards to enter the left kidney, 
where it divides into an anterior and posterior vessel (figs. 10 and 14, 2. renal art.). 
(4) Postertor intestinal and cloacal artery.— This forms a branch which runs 
downwards towards the median line between the right and left kidneys. It divides 
into two branches. One of these runs anteriorly and slightly dorsally till it touches 
and becomes attached to the ventral wall of the lung. From this point branches are 
given off to the dorsal wall of the intestine (figs. 6 and 12, Aost. x¢. art.). The other 
runs backwards between the two kidneys and breaks up into branches, which supply 
the parts in the cloacal region (figs. 10 and 14, clo. avt.). 
(8) The right side. 
(a) Ceeliaco-mesenteriec artery. 
As pointed out by Giinther, this arises from the aorta on the right side 
immediately in front of the subclavian (= brachial artery of this side). In Elasmo- 
branchs (as Mustelus) it arises comparatively close to the entrance of the last 
epibranchial artery into the dorsal aorta and in Amphibia the corresponding vessel 
arises from close to the union of the systemic arches or even from one of the latter. 
In Ceratodus a considerable interval separates it from the commencement of the 
dorsal aorta. 
Owing to the extreme shortness of the alimentary canal in Ceratodus—a point 
of strong contrast between the latter and either Elasmobranchs or Amphibia (except 
certain Urodeles, such as Proteus), and of resemblance between the Dipnoi and 
Holocephali—together with the absence of any clearly marked stomach and owing 
also to the fact that it gives off the anterior spermatic (or oviducal) artery of its side, 
this vessel has somewhat different relationship from that which obtains in the case of 
the artery of the same name in Elasmobranchs. 
In Ceratodus it forms a large vessel which runs at first outwards but soon turns 
downwards and then backwards and runs ventrad of the brachial artery to enter 
the body cavity where the liver is attached to its walls anteriorly. Piercing the 
liver it gives rise to three main branches (fig. 14) :— 
