470 MR. F. E, BEDDARD ON THE [Nov. 28, 
after giving off at any rate one intercostal twig, divides into two 
slender trunks diverging right and left. Hach of these separates 
from itself immediately after its own origin a vessel which 
rapidly plunges into the thickness of the body-wall in the middle 
line, and which represents on either side the anterior vertebral 
arteries of other Lizards. In spite of the limbless character of 
this Ophisaurus, the subclavians are still more distinctly re- 
cognisable as such than they are in Amphisbena. 
The left aorta gives off several vessels to the cesophagus before 
joining the right aorta, but no intercostals. On the other hand, 
the right aorta gives off several intercostals before joining the 
left. Rathke mentions cesophageal arteries as arising from the 
right aorta. 
The carotid artery does not pass up the neck alongside of 
the trachea. But the windpipe is, as in other Lacertilia, accom- 
panied by an artery. This artery, however, in Ophisaurus is 
only to be seen on the right side of the trachea; on the left there 
is at most a rudiment of the same. It gives off branches to the 
thyroid which correspond to those given off on the left side by 
the carotid arch before it gives off the carotid artery. This 
tracheal artery-arises, as do the corresponding pair in Hatéeria, 
&c., from the pulmonary artery. In Ophisaurus it is accom- 
panied by a vein of larger calibre than itself, which runs up the 
neck in close contact with it and again only on the right side. 
On the left I could discover no traces of a corresponding vein. 
This vein joins the anterior cava. The asymmetry in this part 
of the arterial system is noteworthy, for the reason that it is the 
only part of the arterial system which shows, in correspondence 
with the snake-like habit of body, any traces of an asymmetry. 
The dorsal aorta gives off ventrally a regular paired series of 
intercostals, which fail apparently nowhere and are even and 
regularly paired throughout. 
sophageal and Gastric Arteries.—A striking feature of this 
Lizard as compared with many is the very large number of 
trunks arising from the aorta which supply the csophagus 
and stomach. There are two or three cesophageal vessels arising 
from the left aorta before it joins the right. After the junction 
there are seven small arteries still supplying the cesophagus. 
Of these, which are not mentioned by Rathke, the first four 
arise from the aorta itself. After these come three trunks, 
which arise not from the actual aortic trunk but from the inter- 
costal vessel of the left side. All of the cesophageal arteries 
are very small and at the same time very convoluted in their 
course. Following them are five gastric trunks, which are all of 
greater calibre than the cesophageal vessels. The last three of 
these are particularly important. A considerable gap separates 
these gastric vessels from the three chief arteries which end upon 
the walls of the intestinal canal. Hochstetter has figured three 
variations in point of origin ofthese threearteries. In the individual 
dissected by myself I found one of these three arrangements to 
