326 PROFESSOR OWEN ON THE GENUS DINORNIS. 



exhibit the same imperfect coalescence of the proximal ends of the primitively distinct 

 metatarsals which characterizes the above-cited tarso-metatarsal of the young Din. gi- 

 ganteus. In the tarso-metatarsal bone of the Din. curtus, figured in PI. XLVIII. fig. 6, 

 the coalescence is as complete as in the corresponding mature bones of all the larger 

 species of Dinornis. Besides, it difl^ers from the tarso-metatarsal bone of the Din. didi- 

 formis not in size only, but in shape and proportions, the shaft being broader in pro- 

 portion to the length of the bone. 



The information derived from the specimens of Dinornis transmitted to this country 

 since the publication of Part 3. Vol. iii. of the ' Transactions of the Zoological Society,' 

 may be summed up as follows : — 



Confirmation of the deductions as to the rudimental development of the wings in the 

 genus Dinornis, by the discovery of the keel-less sternum, and the evidence it afibrds of 

 the small size of the coracoid bones. 



Confirmation that the species of this essentially terrestrial genus were heavier and 

 more bulky birds in proportion to their height, more powerful scratchers, and less swift 

 of foot than the Ostrich*, but in different degrees, according to the species. 



Indications of an aSinity to the Dodo in the shape of the cranium ; but with evidence 

 of a lower development of the cerebrum, whence the Dinornis may be inferred to have 

 been a duller and more stupid bird. 



Confirmation of the species — 



1 . Dinornis giganteus. 



2. ingens 



3. • struthoides. 



4. dromioides. 



5. didiformis. 



6. otidiformis. 



* A correspondent of the ' Polytechnic Journal' for July 1843, commenting on my description of the fragment 

 of the femur of the Movie, in the ' Proceedings of the Zoological Society,' November 1839, objects : " Neither 

 does its femur furnish reason to conjecture that it was swift or slow of foot." (p. 7.) I have not however drawn 

 any absolute conclusion as to the rate of locomotion of the Dinornis. My remark was merely comparative, as 

 respected the Ostrich. In this large existing bird, which is remarkable for both its swift and long-sustained 

 course, the femur is filled with air, like that of a bird of flight. In the fragment of femur which first indicated 

 the genus Dinornis, I found the cavity of the bone much smaller than in the Ostrich, with evidence that it had 

 contained marrow ; the bony walls being thicker, the cancellous structure more e.\tensive, and the whole bone 

 heavier than in the Ostrich. The femur of the Dinornis therefore did furnish not merely ' reason for conjecture,' 

 but grounds for legitimate physiological conclusion, that that extinct bird was heavier and less swift-footed than 

 the Ostrich. 



The proportions of the other bones of the leg which have since arrived establish the accuracy of the conclusion 

 deduced from the structure of the femur; the metatarsal bones being in the Dinornis one- third shorter and 

 thicker in proportion than in the Ostrich, thus rendering the legs more lilte those of the Apteryx, and conse- 

 quently more like those of the Gallinaceous birds than in any of the existing large Struthious tribe. 



