195 



MEGALAPTERYX haast. 



RIGINALLY distinguished by Haast from the Dinornithidae as an 



ancient form of the Afiterygidae, but afterwards united by Lydekker 

 with the Dinornithidae. Mr. Lydekker' s diagnosis of the genus is 

 as follows : — 



" Distinguished from Dinornis by the extreme slenderness and length 

 of the femur and tibio-tarsus, and the relatively shorter tarso-metatarsus, of 

 which latter the length is considerably shorter than that of the femur. The 

 pelvis is much narrower than in Dinornis, with the ventral surface of the 

 postacetabular sacrals ridged and narrower, and a more developed pectineal 

 process to the pubis. The femur is markedly curved forwards, with the distal 

 extremity moderately expanded, the popliteal depression larger and less defined, 

 the linea aspera narrower and sharper, and a more distinct anterior inter- 

 muscular ridge." 



The following additional diagnostic characters are taken from 

 Mr. Charles W. Andrews' description of the complete skeleton of Megalap- 

 teryx tenuipes in the Tring Museum (Nov. Zool. IV, pp. 188-194, fig. 1-2 in 

 text and pi. VI) :— 



Width of cranium at paroccipital processes less than half the length of 

 the basis cranii. Length of premaxilla less than two-and-a-half times that of 

 the basis cranii. Body of the premaxilla pointed and slightly decurved ; its 

 length and breadth less than the basis cranii. The occipital plane slightly 

 declined backwards. Occipital condyle projecting slightly beyond the parocci- 

 pital processes. Anterior and posterior lambdoidal ridges separated by a very 

 narrow interval in their middle region only. Width at squamosals slightly 

 more than double the length of the basis cranii. Mammillary tuberosities not 

 very prominent. Margin of tympanic cavity evenly curved. Temporal fossae 

 very large. The distance between the temporal ridges about four-fifths the 

 width of the cranium at the fossae. The posterior temporal ridge confluent 

 with the lambdoidal ridge. Post-temporal fossae very large. 



The inferior temporal ridge is strongly marked, and there is a pretympanic 

 process. The zygomatic process is well developed. Rostrum dilated towards 

 its anterior end, compressed and carinate beneath the large presphenoid fossae. 

 Mandible very slender. Posterior angular process small. Sternum very convex, 

 and with a very nearly straight anterior border between the tuberosities for 

 the coracoscapular ligaments. Costal processes short but large, with distinct 



