462 MR, F. E. BEDDARD ON THE | Nov. 28, 
Arterial System.—The arrangement of the aortic arches is pre- 
cisely like that of the Lacertilia. It is not so different from that 
of Lacerta, Iguana, &e. as is the arrangement found in Varanus. 
The carotid arch gives off the usual three branches before joining 
posteriorly the aortic arch. The third branch, that to the 
muscles of the shoulder, arises just before the carotid arch joins 
the aorta. 
As to the systemic (aortic) arch (see text-fig. 59), it is in- 
teresting to note that on both sides this arch gives off an 
esophageal artery; frequently, as is well known, the right arch 
alone gives off such a branch. Just at the meeting of the two 
aorte the subclavians arise. A careful dissection shows (see 
text-fig. 59, Sel.) that both subelavians arise close to each other— 
and onea little in advance of the other—from the right aortic arch 
only just before it joins the left. Hach subclavian gives off im- 
mediately after its origin a forwardly directed vertebral artery, 
which plunges at once into the parietes. Immediately after the 
junction of the two aorte arises the first pair of intercostals. 
Between this pair and the next arises a gastro-cesophageal artery. 
This artery is separated from the gastric by three pairs of inter- 
costals, and five pairs of intercostals lie between the gastric and 
the superior mesenteric artery. The intestinal arteries I need 
not refer to, as they have been already treated of by 
Hochstetter *. 
It may be mentioned that, as in some other Lizards (e. g. 
Gerrhosaurus t), the pulmonary arch gives off on each side a 
branch which runs along the windpipe and sends off branches to 
the thyroid. 
Venous System.—There is no question that, apart from details, 
the venous system of Hatteria is distinctly Lacertilian. Nor 
do the differences which it shows from Lacertilia tend to prove 
a nearer resemblance to the Chelonia or to the Crocodilia. On 
the other hand, I believe it possible to detect likenesses to the 
Ophidia. This, however, in my opinion, does not argue a special 
affinity between Hatteria and the Ophidia, but the antiquity of 
the Hatteria type, which paleontology, as is well known, has 
proved. 
The Lacertilia are distinguished by the double vena cava 
posterior, which is double, that is to say, as far forward as the 
gonads, from which point onwards there is but a single trunk 
formed by the fusion of the two trunks. As a rule, also, there is 
an asymmetry between the two venz cave, or efferent renals, 
as they are commonly termed. When there is this difference, 
the right vessel is of greater calibre than the left. In Hatteria we 
meet with the same conditions, and here the left vena cava is of 
distinctly less calibre than the right. The two vessels, moreover, 
* Morph. Jahrb. vol. xxvi. p. 217. 
+ Beddard, “Anatomy of Gerrhosawrus,” P. Z. S. 1905, vol. 11. p. 263, text- 
fig. 37, P. 
