216 ME, "W. P. PYCRAFT ON THE MOEPHOLOGY AND 



The following pair (7th thoracic) are long, but without sternal segments; the 8th 

 pair are short and fuse with the pre-ilium. 



In Rhea there are two free cervicals, three pairs of thoracic articulating with the 

 sternum by sternal ribs, and provided with very long uncinates. The 4th and 5th 

 pairs are long, but have no sternal segments. The 6th pair are very short and fuse 

 with the pre-ilium. 



Amongst Dinornithidce there appears to be some variation. 



In Dinornis maximus there are three free cervicals, two thoracic connected with the 

 sternum by sternal segments, one long free rib, and three free ribs behind this 

 overlapped by the pre-ilium. 



In Pachyornis there seems to have been but one free cervical or cervico-thoracic, 

 three thoracic articulating with the sternum, four long free ribs, and short free ribs, 

 these last two being overlapped by the ilium. The uncinates were very long. 



In Apteryx the ribs are remarkable for the great breadth and flatness of their 

 vertebral segments. There may be one or two pairs of cervico-thoracic ; there are four 

 thoracic articulating with the sternum (in a skeleton of A. australis I found five on 

 one side, and in a skeleton of A. oweni, both in the Rothschild Coll., I found but 

 three thoracic vertebrae connected with the sternum) and four pairs of free ribs behind 

 these, all of which are overlapped by the pre-ilium. The last pair are often 

 exceedingly short. Six pairs of ribs bear uncinates, the series commencing in the 

 last cervico-thoracic. The uncinates are long and broad, extending backwards to the 

 hinder border of the rib next behind. 



In the ribs of all the Palwoc/nathoe, save Apteryx and some Tinamous, there is a 

 large pneumatic aperture lying in the cleft between the tuberculum and capitulum. 



The Steknum and Pectoral Arch. 



a. The Sternum. 



As with the other portions of the skeleton so far examined, so with the sternum, 

 Dromceus possesses the most generalized type. 



The sternum of the young Lromceus and that of the young Casuarius are very 

 similar in appearance ; in the adult they are readily distinguishable. 



In the adult Drommis the anterior lateral processes are very long, slender, and 

 directed upwards and backwards. There is no spina externa nor interna, but a deep 

 emargination in their place. The ventral lips of the coracoid grooves are well 

 developed. The articular surfaces for the coracoids are short, not exceeding in 

 length the distance between the articulation for the first and third sternal ribs. 

 These grooves differ from those of all the other Palwognathoe in that they overlap, 

 causing the bases of the coracoids to cross one another in the middle line as in many 

 Carinataz. 



