1914,] NATURAL SCIENCES OF PHILADELPHIA. 289 



trachea. At first it is a gutter of bronchial tissue, from the edges of 

 which the ends of the cartilages project into the lumen of the lung 

 for a distance of .3 mm. 



The right lung extends from the 54th to the 114th gastrostege. 

 It is lined with pulmonary tissue to about the 100th gastrostege; 

 the terminal portion ends as a blunt and stout-walled anangious 

 air-sac. There is an apex, 2.5 mm. long, and adherent to the right 

 side of the trachea. The wall between the apex and the trachea is 

 formed of pulmonary tissue alone, there being no fibrous tissue 

 dividing the two structures. The lumen of the apex opens into the 

 lung by a simple tube that is pentagonal in shape and appears to be 

 a single air-cell that is deeper than the rest. 



The left lung, 6 mm. long, is lined with air-cells. The bronchus, 

 at the level of the 58th gastrostege, is a minute opening from the 

 ventral wall of the trachea. 



The left lobe of the liver extends from the 73d to the 11 1th gastro- 

 stege. At this point the posterior vena cav^ begins to furrow the 

 organ and to form the right lobe. Posteriorly the two lobes end 

 nearly at the same level, the right being but 1.5 mm. the longer. 



The gall-bladder is 6 mm. long. The cystic duct flows forward for 

 1.5 mm., and is composed of several tubes. The hepatic duct divides 

 into several branches; these anastomose with the cystic duct to form 

 a complex rete which is 7 mm. long and flows anteriorly to enter the 

 pancreas. The usual condition in serpents is for the hepatic and 

 cystic ducts to join posteriorly to the gall-bladder. 



The ileum is lined with fine longitudinal folds. The last loop is 

 at the 172d gastrostege; from this point it is nearly straight. At 

 the 176th gastrostege there is a sacculated dilatation 3 mm. long and 

 about one-half again the diameter of the gut. The walls are thin 

 and pellucid and the lining is smooth. 



The ciecum is lined with deep longitudinal plicse and there are no 

 transverse septal folds. The ileo-ccecal valve is at the 193d gastro- 

 stege. The csecal pouch is small, being 2.5 mm. long and of about 

 the same diameter; it lies dorsad to the ileum. 



The intercostal arteries are regular, being one for each space. 

 Each arises as a single artery that bifucates below the median line, 

 one fork entering on either side. 



The teeth are of moderate size; the maxillary bears 11, the palatine 

 6, the pterygoid 5, and the dentary bone 12 teeth. 



The floor of the mouth presents unusual conditions. The mandible 

 bends towards the median line, and the anterior tip of the dentary 



