106 Transactions. — Zoologij. 



the outer surface broadest, curved, and rather rough, the two 

 inner surfaces smooth. 



The tihia (tibio-tarsus) is distinguished by the breadth of 

 the cnemial process, by the obhque bony supratendival bridge 

 at the inner anterior surface at the distal end, by the small- 

 ness of the epicondylar tuberosities, and by the prominence 

 anteriorly of the inner condyle. The fibula is not anchylosed 

 to the tibia. 



There is a free post-axial tarsal bone — the second cen- 

 trale" — on the posterior and outer side of the tarsal joint. 



The metatarsus (tarso-metatarsus) is characterized by the 

 smooth and rounded surfaces of the shaft. At the proximal 

 end the depression for the articulation of the inner condyle of 

 the tibia is deeper than that for the outer one. The hypo- 

 tarsal process is grooved, and the outer side of the groove is 

 more prominent than the inner. The interosseous canals from 

 the two posterior foramina unite and open anteriorly by a 

 single foramen. There are no perforations at the distal end 

 of the metatarsal grooves. 1 The inner condyle is more pro- 

 duced than the outer one. 



A hind-toe was probably present in all the species ; and 

 there was a sesamoid on the lower surface of the foot, between 

 the metatarsus and the first phalanx of the inner toe.| The 

 inner toe has three, the middle one four, and the outer toe 

 five phalanges. 



Measurements. 

 In the table of ratios in the genera, those for the leg-bones 

 are the length (L) divided by the girth (G) at the middle of 

 the shaft. For the skull, the breadth at the squamosals (B) is 

 divided by the height (H) at the basi-temporal, and the length 

 from the supra-occipital to the nasals (L) is divided by the 

 breadth at the squamosals. For the sternum, the length of the 

 body (L), measured from the anterior border to a point midway 

 between the two posterior notches, is divided by the breadth 

 of the body (B) just below the costal region. For the pelvis, 

 the length of the ilium (L) is divided by the length of the 

 pre-acetabular portion {I), and the breadth at the anti- 

 trochanters (B) is divided by the length (I) of the pre- 

 acetabular portion of the ilium. 



* Parker, Phil. Trans., vol. clxxxii., p. 100, footnote ; Ext. Birds of 

 N.Z., pi. cxiv., figs. 3-6 (sesamoid). Coughtrey, Trans. N.Z. Inst., vol. vii., 

 p. 2C9 (calcaneo-sesamoid). BuUer, Birds of N.Z., 2nd ed., vol. i., p. xxxu., 

 and vol. ii., p. 333 (astragalus). 



t In one specimen of D. firmus I have seen an osseous briclge over 

 the channel between the middle and inner metatarsal condyles, the per- 

 foration answering to that between the second and third metatarsals in 

 Megalapteryx. 



X Ext. Birds of N.Z., pi. Ixxi., fig. Is. 



