( 193 ) 



the tulierosities for the coraco-scapular ligaments, which are fairly- well marked, l.al erad 

 of these tuberosities the anterior edge rises to form the front border of the antero- 

 lateral processes. These are large, and at their bases there are well marked coracoid 

 pits (c.p.). The lateral borders of the sternum diverge from one another from the base 

 of the antero-lateral processes to the tips of the postero-lateral ])roeesses, which are long, 

 di.stally expanded, and extend considerably beyond the median process. This latter 

 has an iiTegular extremity with an unsymmetrical notch. The whole sternum is 

 short and broad, and is highly convex from before backward as well as from side 

 to side. 



There are three pairs of facets for the sternal ribs. 



The anterior sternal rib is short and .stout (45 mm. in length), the middle one 

 more slender and longer (68 mm.), while the posterior is still longer and very slender 

 (95 mm.). 



The dimensions of the sternum are : — 



Width at antero-lateral processes .... 104 mm. 



Length from tip of antero-lateral to ti]i of postero- 

 lateral process . . . . . . . 141 „ 



Length in middle line ...... 129 „ 



Least width of body (in front of first rib-facet) . . 100 ,, 

 Length of postero-lateral process . . . . 87 „ 



Boxes of the Hindlimi!. 



The femur is of the same slender forwardly arched form as that of M. hectari, 

 though of course considerably larger. There are, however, some structural differences ; 

 thus the neck is less clearly defined, the trochanter projects farther forward, and, at 

 the lower end of the bone, the outer condyle is relatively larger and projects farther 

 backward. In other respects, e.g. in the form of the popliteal fossa and of the 

 articular surface for the fibula and in the arrangement of the intermuscular ridges, 

 the femora of the two forms are similar, and on the evidence of this bone alone it would 

 be possible to refer this species to the genus Mcr/alapteryx without hesitation. 



The tibio-tarsiis is important because upon it depends the identification of tlie 

 species. The tibia upon which Lydekker founded M. tenuipes is unfortunately much 

 abraded, and the width of the distal extremity is thus reduced by about 13 mm. 

 From this it follows that the measurements given in the diagnosis of the species are 

 misleading, as ai.so is the figure (C'atal. Foss. Birds Brit. Mns. fig. 54 c, p. 219). 

 The dimensions of the shaft agree almost exactly with those of the present specimen, 

 and it is therefore a fair inference that those of the extremities in an unworn con- 

 dition were also the same. If this was the case, the ^vidth of the distal end was more 

 than one-eighth of the length of the bone instead of only one-ninth. In M. hectori 

 the proportions were about the .same, and the structure of the whole bone is clo.selv 

 similar. 



I he metatarsus, as in M. heduri, is much compressed antero-posteriorly in the 

 middle of the shaft, and the arrangement of the hypotar.sal ridges and the form of 

 the distal trochleae are identical in the two birds. In the M. tenuipes, however, the 

 intercondylar tubercle is much more prominent and the anterior depression is deeper. 

 Ihe foramen at the lower end of the groove between metatarsals 3 and 4 merely 

 perforates a thin flange of the bone, as in M. hectcn-i ; there is no distal perforatio'n 

 between metatarsals 2 and 3. 



