278 MR. W. P. PYCRAFT ON THE MORPHOLOGY AND 



Drom/eus. 



a. Length 17 in.; pectineal process well developed; dorsal border of pre-ilium 



much arched ; obturator fissure nearly closed ; pubo-ischiadic fissure nearly 



closed D. novos-hollandia. 



b. Length 9^ iu. ; pectineal rjrocess obsolete ; dorsal border of pre-ilium not 



arched; obturator fissure wide : pubo-ischiadic fissure very wide .... D. ater. 



E. Pectoral Limb. 



A. Extended forearm and hand longer than the humerus ; ulnare resembling 



that of the typical Neognathse ; radius and ulna long, with hut a narrow 



chink between them ; distal end of Me. II. flabelliform Rhea. 



B. Extended forearm and hand much shorter than the humerus. 



a. Humerus with a shallow, but blind subtrochanteric fossa; a very strongly 



developed linea aspera for the triceps, forming a conspicuous triangular 

 ridge; radius and ulna short and bowed; ulnare a simple nodule; distal 

 end of Me. II. not markedly expanded ; manus as in Rhea, resembling 

 typical carinate form, though too small for purposes of flight .... Struthio, 



b. Humerus much bowed, without subtrochanteric fossa or indication of 



pectoral crest ; radius and ulna with but a very narrow chink between 

 them ; a vestigial radiale and ulnare ; a vestigial pollex bearing an 

 unequal phalanx, with the Me. III. incomplete and free distally . . . Apteryoo. 



C. Extended forearm and hand about equal to the length of the humerus ; a 



subtrochanteric fossa ; radiale and ulnare anchylosed with metacarpals. 



a. Subtrochanteric fossa large ; ulnare indistinguishable ; radiale anchylosed 



with radius and carpo-metacarpus, but distinguishable Casuarius. 



b. Subtrochanteric fossa very small ; no carpal elements distinguishable ; 



neither pollex nor third digit represented : . Dromaus. 



F. Pelvic Limb. 



When the bones are pneumatic only the femur is conspicuously so ; save in the Dinornithidoe 

 the extensor bridge is wanting; the hallux, when present, is never large. 



a. Toes three in number; tarso-metatarsus far exceeding femur in length. 

 a'. Ectocnemial crest large, rivalling the procnemial in size ; ento-condyle with 

 a deep lateral pit ; distal extremity of shaft above entocondyle (lateral 

 surface) with a deep groove. 

 a". Procnemial crest extending down the shaft ; femur with a large 



pneumatic aperture Drommus. 



b". Procnemial crest not extending down the shaft ; femur non-pneumatic; 



ungual phalanx of inner toe greatly elongated Casuarius. 



b'. Ectocnemial crest small, a mere tubercle of the procnemial; no ento- 

 condylar pit or groove on the lateral surface of the shaft ; a moderately 

 conspicuous extensor groove ; popliteal fossa of the femur very deep ; 

 ungual phalanges laterally compressed Rhea. 



