1905.] OF THE YELLOW-THROATED LIZARD. 265 



The left systemic arch gives off no branches at all that I could 

 discover. 



Fi'om the right systemic arch (which joins the left at about 

 the commencement of the lung) the two suhclavians (text- 

 fig. 37, Scl., p. 263) are given off, nearly, if not exactly, opposite 

 to each other. In front of this arises the vertebral artery {I.e.), 

 which gives off an oesophageal branch before plunging into the 

 thickness of the parietes. Behind the vertebral artery commences 

 the series of intercostals. The first intercostal artery arises just 

 before the junction of the two aortse. It gives off a branch to the 

 oesophagus. The next two intercostals have also oesophageal 

 branches ; but it is to be noted that in all these the right inter- 

 costal alone has this oesophageal branch. The left has none. The 

 remaining intercostals have no oesophageal or gastric branches. 

 Their arrangement is peculiar and agrees with that of the iSkinks ; 

 it differs from that of some other Lizards. 



In Tropichirus hisjndus, for example, the regularly paired 

 intercostals emerge from the dorsal aorta close to the articulation 

 of successive vertebrae, and plunge at once into the thickness of 

 the parietes. 



In Gerrhosaurus the intercostal arteries emerge from the 

 aorta at about the middle of each vertebra. In many cases, 

 and the arrangement is roughly alternating, the intercostal of 

 one or both sides divides at once into two branches ; one of these 

 plunges at once into the thickness of the parietes. The other ' 

 passes obliquely forwards and runs superficially in close relation 

 to a rib. This, however, only occurs in the thoracic region, not in 

 the lumbar. 



Precisely the same disposition of vessels is found in Eumeces 

 and some other Skinks, and the fact is a bond of union between 

 the Gerrhosauridse and Scincidre. 



The next artery to arise from the aoita is a gastro-oesophageal 

 (text-fig. 37, ces, g, p. 263, and text-fig. 38, oss, (/\ p. 264), which 

 divides at once into a thin forwardly directed oesophageal, and a 

 stout backw^ardly directed gastric. Between this and the lai-ge 

 gastric artery (text-fig. 38, g') are 6 jDairs of intercostals. Two pairs 

 intei'vene between this artery and that of the large intestine, and 

 one pair between the latter and the arteiy of the small intestine. 



The ovarian and oviducal arteries present some features wdiich 

 are worthy of note. There are three pairs of oviducal arteries 

 which are not symmetrical. The first of these is really mainly aii 

 ovarian artery, which gives ofi" a thin and slender oviducal branch 

 running along the anterior section of the oviduct. The two 

 remaining oviducal arteries arise in common with an intercostal. 

 They lie in front of the i-ectal artery. 



Venous Systevi. 



Although the venous system of neither of the examples at my 

 disposal was injected, most of the veins were beautifully displayed 

 by their own turgescence. 



