phyl()(;exy of the pal^ognath^ and neognath.e. 277 



b. Post-acetabular ilia closely approximated, the neural spines at most only 



barely visible between the closely approximated iunomiuates ; no supra- 

 trochanteric process ; iseliia widely separated from post-acetabular ilium; 

 obturator foramen and fissure confluent ; post-sacral vertebra of the 

 synsacrum welded into a large laterally compressed mass, bent down so 

 as to bring the neural crest to the level of the ventral border of the post- 



'■'"i" Apteryx. 



B. Pubes auchyloscd caudad with one another or with ischium. 



c. Post-acetabular ilia widely separated from iscliia, and from one another 



in the mid-dorsal line ; pubes fused caudad («) with the ischia and (6) 

 with one another in the mid-ventral line ; the synsacral vertcbrce appear- 

 ing below the level of the ventral border of the ilium Struthio. 



d. Post-acetabular ilia anchylosed with ischia, and with one another in the 



mid-dorsal line; pubes anchylosed with ischia caudad; ischia clusclv 

 united in the middle line one wdth another throughout almost entire 

 length (uuique) ; the post-sacral vertebra; of the synsacrum atrophied . Rhea. 



Keij to tlie Species, 



Rhea. 



a. Pre-ilium not projecting forward beyond the last thoracic vertebra and rib, 



which forms the limit of the synsacrum cephalad R, americana. 



b. Pre-ilium projecting forward conspicuously beyond the last thoracic vertebra 



^^^ ^^^ R. macrorhyncha. 



Apteryx. 



A. Width across anti-troehanter equal to or less than the width of pre-acetabular 



ilium at widest. 



a. Pre-acetabular ilium of great width, with a strongly arched dorsal border, 



and large laterally expanded antero-vcntral angles ; width across pre- 

 acetabular ilia at widest part = to length of ischium, and far exceeding 

 length of post-aeetabular ilium ; post-acetabular ilium with a sudden 

 widening at its free end ; breadth of pre-ilium at widest = breadth across 

 auti-trochanter A.australis. 



B. Width across anti-troehanter always greater than width of pre-acetabular 



ilium at widest ; post-acetabular tapering caudad ; breadth of pre-ilium at 

 widest less than breadth of anti-troehanter. 



b. Pectineal process large ; five lumbar vertebrse. 



a'. Post-aeetabular ilium with a concave ventral border, and a slight notch 



immediately behind the anti-troehanter ^. Uaasii. 



b'. Post-acetabular ilium with straight or convex ventral border ; no notch 



behind the auti-troehauter ^. oweni. 



c. Pectoral process small ; four lumbar vertebrse A. a. inantdli. 



VOL. XV. — PARTY. No. 22. — Decemher^Vd^^. 2 q 



