634 Transactions. — Geology. 



DlNORNIS TOROSUS. 



D. stnithioides (part), Owen. 



D. gracilis and D. stnithioides, Haast. 



D. sp. (rohustus) and D. struthioides (part), Lydekker. 



D. torosus, D. strenuus, and Pal. plena, Hutton. 



The number of leg-bones measured was — metatarsi, 55 ; 

 tibJEe, 33 ; femora, 35. The stermim has a width of 5-5in. to 

 6-2in. just below the costal border. The length of tho, 2) elv^s 

 is about 17in. ; its width at the antitrochanters Sin. ; and 

 the depth of the antacetabular portion of the ilium about 

 Sin. 



This species is well marked oft" from D. rohustus, and 1 

 was evidently quite wrong in subdividing it. There are not 

 two sizes, but each bone shows a single point of concentration. 

 Here, therefore, we have good evidence that the two sexes 

 were practically identical m size, and consequently it is 

 probable that the same held good with the larger species of 

 Dinornis. Certainly it does away with any argument based 

 on the different sizes of the sexes in AiJteryx. 



Genus MEGALAPTERYX. 



Thefemtir has a short head with slightly constricted neck. 

 The shaft is slender, slightly compressed laterally in the 

 middle, and the anterior surface is curved longitudinally in 

 the antero-posterior plane. The iinea aspera is well marked, 

 but the popliteal tuberosities are obsolete. The popliteal 

 depression is short and shallow. The distal intercondylar 

 fossa is deep on the inside and shallow on the outside. 



The length of the tibia is 12 to 14 times its width in the 

 middle. The procnemial ridge is nearly straight. The shaft 

 is convex both before and behind, and is more nearly oval 

 in transverse section than in any other genus. The ex- 

 tremities are but slightly expanded, and the extensor bridge 

 and tubercle are directed above the top of the outer con- 

 dyle. 



The length of the metatarsals is between 6 and 7 times the 

 width in the middle. The proximal articular surface has both 

 its inner and outer margins rounded. The foramina above the 

 insertion of the tibialis anticus usually open anteriorly into a 

 deep depression, and their posterior openings are nearer 

 together than in other genera. The posterior surface of the 

 shaft is more rounded than in any other genus. The trochlete 

 diverge strongly : the second is short, its outer surface with a 

 deep depression, and its base markedly broader than that of 

 the fourth. The two trochlear gorges are of about equal 

 depth. 



