46 



R. J. Anderson, 



Myrmacophaga tetradactyla. 

 Length of the upper part of the thorax, 190 mm. 





1 



2 



3 



4 



5 



6 



7 



8 



9 



10 



11 



12 



13 



14 



15 16 



17 



Length of 

 ribs 



35 



43 



47 



52 



55 



56 



60 



67 



68 



70 



70 



70 



65 



65 



60 



45 



30 



Length of 

 Cartilages. 



13 



18 



20 



25 



31 



35 



40 



45 



53 



70 



— 



— 



— 



— 



— 



— 



— 



Lower end. 



4 



8 



9 



7(r) 



4(r) 



3,5(t) 



4,5 



5 



5,5 



6 



7 



7 



6 



5 



4 



3 



2,5 



Broadest 



part. 



9 



12 



9 



8(t) 



8(t) 



8(t) 



8 



8 



7 



7 



7 



7 



6 



6 



4 



5 



6 



Distance of 



the Broadest 



part 



from end. 



10 



10 



— 



35 



45 



47 



45 



45 



50 



45 



45 



45 



45 



45 



40 



33 



a 



1 



■3 



The broad surfaces of the first and second look forwards. The 

 3'^ also, but superiorly surface of this rib begins to look outwards and 

 inwards. The fourth has a wide tangential diameter above I indicate 

 by (t). The radial breadth is indicated by (r). 



The great breadths as the lower extremities of the second, third 

 and fourth ribs correspond to the same surface breadths at the upper 

 parts of the ribs. 



Behind the sixth the lower ends commence to widen again and 

 then the surfaces look backwards as well as outwa,rds whilst the upper 

 widening which is tangential looks forwards as well as outwards. 



The surfaces of the ribs below are at right angles to the surfaces 

 above. The surfaces look more and more outwards as the ribs are 

 traced backwards. So that the posterior ribs look outwards and 

 upwards. 



The lower borders of all the ribs from the third to the fifteenth 

 have thin lower borders in the middle thirds of their lengths. The 

 thinness is produced at the expense of the inner surfaces. 



The ribs are compressed just outside the tubercles, and again 

 above the lower ends, the ribs except the anterior 2 or 3 and the 

 posterior 2 or three. 



I note that in another skeleton the narrowness of the ribs just 

 below the tubercles is most marked. 



„Sie sind weniger gekrümmt als bei der zweizehigen Art, ihr 

 Hinterrand gleichfalls erweitert aber am unteren Ende nicht nach aussen 

 gerandet, sondern allmählich sich verwischend." (Giebel). 



