488 ON 'THE VASCULAR SYSTEM OF LACERTILIA. | Nov. 28, 
They very largely arise in common with intercostals. They do 
not, however, show the continuous symmetry and regularity that 
is shown by the renal arteries in Ophisaurus. In Amphisbena 
cinerea, v. Bedriaga states the presence of 5—7 pairs of renal 
arteries, of which the first pair are much the largest and are trace- 
able for a long distance along the outer border of each kidney. 
The wtercostal arteries in Amphisbena are upon the Lacer- 
tilian plan, and not upon that shown in the Ophidia in spite of 
the length of the body. They are paired equisized arteries * 
each artery of a pair close together in their origin from the 
ventral surface of the dorsal aorta. Though these pairs are 
regular and repeated with no variation from seement to segment, 
there are nevertheless occasional, but very occasional, indications 
of a divergence in the direction of the arrangement so character- 
istic of the Ophidia other than the Boide. In one case, on the 
left side of the body, a single intercostal artery bifurcated 
immediately after its origin from the aorta and supplied two 
intercostal regions, one in front and one behind. In another 
case an intercostal was wanting on the left side, but a branch 
from the right corresponding intercostal was seen to pass under 
the vertebra and to supply the left side of the body. Very 
generally the intercostals branch before becoming lost to sight 
within the muscles of the dorsal parietes. There are two divisions 
which burrow, and a trunk which runs superficially outwards 
between the ribs. This superficial trunk is to be seen in other 
Lacertilia, particularly among the Scincide. No intercostals 
arise from the left aortic arch, which is, indeed, free from branches 
of any kind. Three pairs arise from the right aortic arch. 
Lungs.—The trachea and lungs of the present species differ 
very considerably from those of Amphisbena fuliginosa, described 
and figured by Wiedersheim?. That author figures the lung 
as extending considerably anteriorly to the heart, and the trachea 
opens into it by a series of short branches of its lower surface. 
The arrangement, in fact, is obviously suggestive of the “ tracheal 
lung” of certain Snakes, and especially of the genus Ophiophagus, 
where, as I myself have recently described, the trachea opens by 
a series of orifices into the pre-cardiac portion of the lung~. An 
almost exactly similar specialisation in a Snake, or rather in many 
Snakes and in a snake-like Lizard, is very remarkable. It seems 
possible, in view of the fact that the tracheal lung exists in Snakes 
of quite different families, and that it also exists in Amphisbena 
fuliginosa§, that this state of affairs is primitive and is to be 
referred to an Amphibian ancestor in which the lung, as in the 
Frog &e., opens at once into the pharynx without the mtermedia- 
tion of any length of trachea. 
* V. Bedriaga, however, figures the first few intercostals as arising in an irregular 
and therefore snake-like fashion. 
if Vergl. Anat. Wirbelth. 2nd ed. 1886, p. 558. 
ng den ZS. 1908, vol. 11. p. 322. 
§ Smalian, however (Zeitschr. wiss. Zool. 1885), does not find this spunea 
