10 



MR. F. E. BEDDARD OX THE 



[Jan. 17, 



does not, as it does in Iguana, overlap the lai'ger compai'tment of 

 the lung posteriorly. It ends exactly on a level with the entrance 

 of the bronchus into the main division of the lung. 



The interior of the lung in both genera is slightly sacculated, 

 and the accompanying drawings (text-figs. 5, 6) illustrate the 

 conditions obtaining in the two genera. It will be noticed that 

 in Clilamyclosaurus the dorsal sacculations, though fewer, are 

 more pronounced and deeper than in Physignathus, while the 



Text-fig. 5. 



y 



IjUiig of Cldantijdoscniriis, opened to sliovv iiitenial titiucture. 



deeper honeycombed structure of the lung itself implies a larger 

 respiratory sui-face and so far a greater efficiency as an organ of 

 breathing. It appears to me to be a fair inference that this is 

 associated with the bipedal and more active gait of Clilamyclo- 

 saurus. In both genera the mesentery tying the lung to the 



