488 ON THE VASCULAR SYSTEM OF LACERTILIA. [iSToy. 28, 



Tliey very largely arise in common with intercostals. They do 

 not, however, show the continuous symmetry and regailarity that 

 is shown by the renal arteries in Ojihisaurus. In Amphisbcena 

 cinerea, v. Bedriaga states the pi-esence of 5-7 pairs of renal 

 ai'teiies, 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 intercostal arteines in Ainiphishcena 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 fi'om segment 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 Boidte. 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 cori'esponding intercostal was seen to pass under 

 the vertebra and to supply the left side of the body. Very 

 geneiully 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 Scinciclae. 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 Amphisbcena fuliginosa, described 

 and figured by Wiedersheim t. That author figures the lung 

 as extending considerably antei'iorly to the heart, and the trachea 

 opens into it by a series of short branches of its lower surface. 

 The aiTangement, in fact, is obviously suggestive of the " tracheal 

 lung " of cei'tain Snakes, and especially of the genus Ophiophagus, 

 where, as I myself have recently described, the trachea opens by 

 a series of orifices iuto the pre-cardiac portion of the lung J. 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 Amphisbcena 

 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 &c., opens at once into the pharynx without the intermedia- 

 tion of any length of trachea. 



* V. Bedriaga, however, figures tlie first few intercostals as arising in an irregular 

 and therefore snake-like fashion. 



t Vergl. Anat. Wirbelth. 2nd ed. 1886, p. 558. 



J P.Z.S. 1903, vol. ii. p. 322. 



§ Smalian, however (Zeitschr. wiss. Zool. 1885), does not find this arrangement. 



