PROFESSOR OWEN ON THE GENUS DINORNIS. 161 



is a small pneumatic foramen below and in front of the diapophysis. The rib, about 

 four inches in length, terminates in a point, and has no sternal portion, nor any 

 appendage. 



Besides the seven pairs of ribs from the seven dorsals, there are two pairs from the 

 anterior sacrals, progressively diminishing in size, and the last terminating freely in a 

 point. The first of these sacral ribs was moveably articulated to the first sacral vertebra : 

 the second is anchylosed to the second sacral vertebra. 



Thus the Dinornis elephantopus had nine pairs of long, conspicuous ribs : the first 

 floating ; the second to the fourth pairs inclusive composed of pleurapophysis and 

 hgemapophysis, the latter articulating with the expanded haemal spine or sternum. 

 The next three pairs had hsemapophyses, or ' sternal ribs ' which did not reach the 

 sternum : the eighth and ninth pairs, simple and pointed like the tirst pair, belong to 

 the first two of the vertebrae that have coalesced to form the long sacrum. 



Of the cervical vertebrse there are fifteen, each having its individual character, and 

 with trochlear articular surfaces so clearly or definitely sculptured on the ends of the 

 centrum as to permit of no mistake in the co-adaptation of the vertebrse, successively, 

 from the last or fifteenth, ib. C 15, up to the atlas, ib. C 1. The size of the articular 

 cup on the fore part of the atlas determined the cranium belonging to the present 

 skeleton of Dinornis elephantopus. 



In the last cervical, ib. C 15, the hypapophysis is a ridge from the front half of the 

 centrum ; which centrum is longer, but of less fore-and-aft extent than that of the first 

 dorsal. The short rib is anchylosed to both parapophysis and diapophysis ; it is an 

 inch and a half in length, pointed and directed backwards. The spine is smaller in all 

 its dimensions than in the first dorsal. 



In the fourteenth cervical, ib. C 14, the hypapophysis is a thick sub-bilobed ridge 

 from near the fore part of the centrum, but is extended transversely, not from before 

 backwards. The rib is merely a bar uniting the ends of the two transverse processes : . 

 the spine is rather more than an inch long, nearly an inch broad, half an inch from 

 before backwards, and bifurcated, with the two divisions on the same transverse line. 



The thirteenth cervical, ib. C 13, has a pair of anterior hypapophyses with their 

 tuberous ends approaching and almost meeting each other, so as to complete a hsemal 

 canal. The median cleft of the short spine almost divides it into two processes. The 

 canal circumscribed by the met-, di- and pleur-apophyses, on each side of the vertebra, 

 is large enough to admit the fore-finger. The centrum appears to be larger than in 

 the succeeding vertebrae, because it does not lose in fore-and-aft extent while decreasing 

 in other dimensions. 



In the twelfth cervical, ib. C 12, the anterior hypapophyses are wider apart: the 

 transverse pair of spines are also more apart, and are shorter than in the thirteenth 

 vertebra. 



In the eleventh cervical, i6. C 1 1 , the hypapophyses are shorter and wider apart : the 

 neural spine is now a pair of tuberosities. 



