PHYLOOENY OF THE PAL.EOGNATH^ A\l) NEOGNATILE. 



lumbar neural spines but little axially extended, but considerably 

 extended dorso-ventrally and not subequal in height ; synsacrum with 

 post-sacrals not at all raised dorsad of acetabula, but rather depressed 

 ventrad ; jwst-sacrals yerfvdhj ossified ; saeral plainly distinct from 

 post-sacral vertebrae; no himbo-sacral vcrtebrte; pre-eaudal vertebras 



ten ; pygostyle a laterally compressed plate .... Sinithio. 



f. Total number of vertebne forty-nine; cervical vertebrie fourteen; pre- 

 axial articular dorsal surface of atlas with only a minute dorsal notch ; 

 no hyperapophysis to atlas; liypapophysis of axis not very large; 

 neural spine of axis not very high ; hyperapophyses of axis well deve- 

 loped ; neural spines of cervical vertebra; almost obsolete, those of 

 fourth to seventh vertebne abort ; neural spines of thirteenth to 

 sixteenth vertebrje bifurcate laterally ; hypapophyses developed from 

 last cervical to second dorsal vertebra; hypapophyses narrow and 

 pre-axially produced ; a conspicuous fossa on each side of pre-axial part 

 of neural spines from twelfth to the fifteenth inclusive ; cervical ribs 

 short and not styliform ; free cervical ribs nine ; synsacrum with post- 

 sacral vertebrae raised quite dorsad of acetabula, also very imperfectly 

 ossified and much reduced ; sacral plainly distinct from post-sueral 

 vertebrae ; post-saerals nine ; free caudal vertebne five ; pygostyle small 

 and cylindrical Rhea. 



273 



The vertebral formula is : — 



Synsac. 



~^ 



DromiTus CV. 18 : Cv. Th. 3 : Th. 3 + 1 + 2 : Lb. (i : Eb. sc. -J : Sc. 2 : Cd. 9 -|- !t = .J5. 



t; 18 



Syusac. 



^ ~ ■ s 



Casuariits Cv. 15 : Cv. Tb. 4 : Th.5-|-l+3: Lb. 5 : Lb.sc.2: 8c. 2 : Cd. 9-|-9 = 5.5. 



9 18 



Struthio 



Synsac. 



Cv. 17: Cv. Th. 3: Th. 5-1-2: Lb. 8 : .Sc. 2: Cd. S-flO 



18 

 Sj'usac. 



Uhea Cv.l4: Cv.Th.3: Th.3-t-2+l: Lb. 3 : Lb. sc. 4 : Sc. 2 : Cd. 9-1-8 = 49. 



6 17 



Synsac. 



Aijteryx Cv.l5: Cv. Th. 1 : Th.4-|-3-fl: Lb. 4 : Lb. sc. 4 : Sc. 2 : Cd. 3-f 8=45. 



(-4. a. manttUi.) " » ' " ' ' 



8 11 



