4 ME. ST. GEOEGE MIVAET ON THE 



of the pleural lamella; and the interzygapophysial ridge may be very conspicuously 

 perforated. 



The third vertebra is again relatively shorter and higher than in Struthio. Both 

 articular central surfaces look more dorsad and ventrad respectively; and the lateral 

 margins of the postaxial one are not, or but very slightly, concave. The hypapophysis 

 extends more postaxiad ; but the nem-al spine does not extend so much preaxiad as in 

 StrutJno. The postzygapophyses look entirely ventrad. The hyperapophyses are as 

 large as in the axis and are grooved pi-e- and postaxially. The neural spine does not 

 rise suddenly preaxially, and is hardly at all preaxially excavated. The interzygapo- 

 physial ridge is perforated, but not so conspicuously as in the axis. 



FOURTH VERTEBEA OF BEEA (natural size). 

 Pig. 5. 



Dorsal view. Letters as before. 



The fourth vertebra is again much shorter relatively as well as absolutely than in 

 Struthio, is more equal in length to the third, and more quadrate when viewed dorsally, 

 its transverse diameters between the prae- and between the postzygapophyses being sub- 

 equal. The neural spine is slightly excavated preaxially, but is deeply so postaxially. 



The fifth vertebra. — The contrast as to length between this and the preceding ver- 

 tebra in lihea is something like that existing between the third and fourth vertebrae in 

 Struthio. The neural arch is not more cut away preaxially than in the fourth vertebra. 

 There is no hypapophysis, and hardly a trace of hyperapophyses. The neural spine (like 

 that of Struthio's fourth vertebra) is reduced in size, and is slightly and subequally 

 excavated at both ends. The transverse diameter of the preaxial part of the vertebra 

 (viewed dorsally) decidedly exceeds that of its postaxial end. 



The sixth vertebra is much longer and more slender, and differs from the fifth much 

 more than does the fifth from the fourth, the increase in length thus taking place later 

 in the vertebral series in Shea than in Struthio. The styliform ribs are very much 

 shorter ; but, as in Struthio, the catapophyses are first marked in this vertebra. The 



