Present distribution of the so called Ratitae. 169 



tarsus, which arc enormcnislv broad and stout, and the toes are 

 much sliorter and stouter. 



S") Pdldeocdsiiftriiis. Ditïers from tlie other ^"enera by the 

 tibio-tarsus beint;' straighter and less twisted on itself, so that 

 the ridge forming" the inner wall of the groove for the tendons 

 of the extensor muscles runs along the inside of the bone as in 

 Casuarlus. 



6. Aepyornithidae. Skull with conspicu(jus cerebral dome; 

 lachrymal fused with the frontal and antorbital plate: Wing 

 vestigial: Sternum recalling" that of Aptenj.v, long, narrow, deeply 

 notched anteriorly, and having rib-facets wide, and well spaced: 

 posterior lateral processes short: metasternal element wanting. 

 Pelvis very broad across post-acetabular region, recalling" that of 

 D'uioniis : the post-ilia being separated by means of the long 

 transverse processes of the synsacral vertebrae: ischia widely 

 separated one from another, and from post-ilia: median dorsal 

 post-acetabular fossa completely roofed by bone, perforated by a 

 double row of foramina, on either side of the middle line: 3-toed, 

 hallux wanting: tarso-metatarsus extremely wnde and flattened 

 antero-posteriorly, no foramen in the groovs between the 3'''^ and 

 4^^^ trochleae: 3''' trochlea much the largest. 



7) Eremopezinae. Very generalized form. Outer condyle larger 

 m proportion to the inner, than in all Ratitae except SfrutJiio; 

 Condyles separated by well marked intercondylar groove, thus 

 resembling Rhea and Casiiarius as opposed to Aepyornis and 

 Struthio; postcondylar processes not nearly as prominent as in 

 Strutiiio, about as in D romains; &gg intermediate between 

 Struthio and Aepyornis. 



I will now try and give a key to the species: in the case of 

 fossil forms I of course can in most cases only give measurements. 



J 



Struthio. 



Smaller, cervical vertebrae shorter and 



stouter, metacarpals thicker . . . . S. asiaticus. 

 Larger, cervical vertebrae longer and 



more slender, metacarpals thinner . No. 2. 



/ Neck and thighs red No. 3. 



\ Neck and thighs blue No. 4. 



j Neck almost naked, top of head with 



thin scattered bristles Struthio camelus. 



■2 



^ Neck covered with down, top of head 



covered with thickly placed bristles ^S*. massaicus. 



I Neck bare, top of head with horny 

 shield S. molyhdophanes. 

 Neck covered with down, no horny 

 shield on head ^S'. australis. 



