42 



E. J. Anderson, 



Ornithorhyncus Paradoxus. 



The greatest diameters of the ribs are radial. The 16*^ lò^^ and 

 14*^^ increase in breadth below the angle and show narrow edges above 

 this point. All the ribs behind the eighth are thicker below the angle. 

 The depth of the thorax, that is, the distance from the first to the last 

 transverse process is 130 mm. The posterior surfaces of all the ribs 

 from the second to the eighth inclusive turn outwards at a distance 

 of about 3 — 4 mm above the cartilages. The cartilages are very wide 

 in the lower ribs. That of the thirteenth rib measures eight mm at 

 a distance of 15 cm from the rib end. 



The following table gives the measurements. 





1 



2 



3 



4 



5 



6 



7 



8 



9 



10 



11 



12 



13 



14 



15 



16 



17 



A 



30 



35 



45 



50 



60 



65 



65 



70 



70 



68 



66 



62 



60 



53 



45 



35 



20 



B 



10 



20 



25 



28 



28 



25 



20 



— 



- 



— 



— 



— 



— 



— 



— 



— 



— 



C 



10 



10 



8 



8 



13 



28 



50 



40 



35 



30 



30 



25 



20 



— 



— 



— 



— 



D 



3 



4 



3 



3,5 



4 



4 



4 



4 



4 



4 



4 



3 



3 



2,5 



2,5 



2,5 



2 



E 



3 



3 



3 



3 



3,5 



3,5 



3,5 



3,5 



3 



3 



3 



3 



3 



3 



3 



3 



2 



V 



2 



2 



2 



2,5 



2,5 



2,5 



2,5 



3 



3 



3 



3 



2,5 



2,5 



3 



3 



2,5 



2,5 



A = Length of the vertebral rib from the tubercle to the lower end. 



B = Length of the sternal rib. 



C = Length of the cartilage. 



D = Breadth of the rib at the lower end. 



E = Radial breadth at the angle. 



P = Tangential breadth at the angle. 



Edddna has the anterior ribs flattened from before back, middle 

 anteroposterior flattening above and interoexternal flattening below. 



Macropus giganteus. 



Giebel says of the Kangaroos generally that, the surfaces of the 

 ribs look forwards and backwards above. Then the upper border turns 

 back and the surfaces are inner and outer below. 



The following table gives the breadths, 



Bibs. 



1 



2 



,,3, 



4 



5 



6 



7 



8 



9 



10 



11 



12 



13 



Radial breadth 

 at Angles. 



15 



14 



13 



12 



10 



10 



9 



9 



9 



9 



9 



9 



9 



Tangential 

 breadth at or 



10 



8 



8 



10 



12 



10 



11 



10 



10 



10 



13 



15 



7 



nearlowerends. 





























