Moasurcmeul of ribs. 



4f> 



Myrmacophaga didactyla. 

 Leni^tli of the dorsal region 90 mm. At side 75 cm. 



No. Rib. j 



1 



2 ! 3 1 4 ' 5 



.1 ' 



6 



7 



8 



9 



10 



» 



12 



13 



14 



15 



IG 

 26 



17 



I.eiigtii of rib. j 17 



20 



23 



29 



30 



30 



35 



33 



33 



35 



35 



35 



30 



28 



26 



15 



Length ij 

 ul° I'artilagc. '} 



— 



8 



7 



9 



10 



15 



18 



25 



15 



— 



— 



— 



— 



- 



— 



— 



Hreadtb , o 

 at lower end. |j " 



2 



2 



2 



2 



1.5 



1.5 



1.76 



2 



1 



1 



1 



1 



1 



1 



1 



2 



(«reatest i .> 

 nroadth. ^ 



5 



4 



5 



6 



6 



6 



6 



6 



6 



7 



7 



6 



5 



.O 



4 



3 



I>istanco of 



■3 



'S 



5 



a 





'S) 



"to 



e 

 S 



1 

 a 





















the i r 



5 









a 



a 



el 



* 





























fl 

































d 









angle frorae 11 2 m 



the £ ■ 5 



^ 







. 





a 



a 

 a 



•0 







CO 



•T3 



•a 







•0 



•0 









^ 





S 



a 









rH 





■* 























eg 























lower end 



2 1 a 









•a 



10 







"5) 



a 







"5) 



C3 



































<i 



<^ 





















The overlap is best marked in the space lying between the spine 

 internally and a line 25 mm. external to the spine in the middle of 

 the dorsal region. 



The imbrication is favoured by the thinning of the anterior edge 

 at the expense of the outer surface and of the posterior border of the 

 ribs at the expense of the internal surface. 



The external thinning reaches quite 2 mm. in the middle dorsal 

 region, to that only 2 — 3 mm. of rib is single at this place. 



The opposite surfaces are thinned also so that the ribs except the 

 first two show a distinct thickening along the middle of their breadth 

 and anterior and posterior thin borders. 



The tangential breadths are the most prominent features. 



I note also that two sets of tubercles are present as the angles 

 and to a line 3 mm outside the angles. 



The 7'^ S"«, "J'h, 10"' and 11"' ribs have each a groove on the 

 inner and posterior parts of the lower ends. There is a slight trace 

 of this groove in the sixth and 13'^- 



The length of ribs means the length from the tubercles to the 

 lower ends. 



Prof. Giobcl mentions the two rows of tubeicles and has also 

 noted the character of the inferior border below (op. cit. 378). The 

 notching of the posterior borders is also mentioned by the same writer. 



