258 PEOFESSOE OWEN ON THE GENUS DINOENIS. 



(=70 millim.) ; to the back of the palpebral opening is 3 inches 6 lines ( = 8G millim.) ; 

 the longitudinal extent of that opening is 9 lines ( = 20 millim.). From the beak-tip 

 to the hind border of the ear-aperture (ib. e) is 4 inches 8 lines (=120 millim.) The 

 length of the tegumentary aperture is 9 lines ( = 20 millim.) ; its vertical diameter is 

 7 lines ( = 13 millim.). 



The sclerotic bone-ring of the dried eye-ball projects from the left orbit ; a few of 

 the ossicles are exposed (ib. fig. 2) ; their total number seems to have been twelve. 

 The relative size of the organ of vision, as compared with that in Apteryx, favours the 

 assumed diurnal habits of Dinornis, in which also it accords with the relative size of 

 the optic lobes indicated by their fossse in the bony walls of the brain-case '. 



The head is preserved with the mouth widely open ; the length of the gape is 

 3 inches. 



Not any of the feathers are preserved on the cranial integument, but their pits of 

 insertion are manifest, slightly increasing in size toward the occiput and upon the 

 cervical integument, where the pits become prominent. 



Within the mouth may be seen the hypobranchial elements of the thyrohyals ', each 

 1 inch 8 lines (=43 millim.) in length ; the dried remains of the tongue anterior to 

 these bones are preserved, including the antroverted ceratohyals and the basihyal (ib. 

 fig. 4). From the beak-tip to the fore border of the palato-nares is 2 inches 2 lines 

 (=54 millim.). 



The upper larynx, with the trachea, as far as the ninth cervical vertebra, is preserved. 

 The tracheal rings are bony and entire, showing a full oval diameter of the windpipe, 

 7 lines ( = 16 millim.) by lines ( = 14 millim.) (ib. fig. 5); each ring shows a breadth 

 of nearly 3 millim., with a thickness of nearly 1 millim. They are not quite the size of 

 the smallest tracheal ring (fig. 10, a-c, pi. xlvii. Trans. Zool. Soc. vol. vii. 1870) 

 referred, with a 1, to Dinoriiis rhe'ides; but they give welcome confirmation to the 

 ascription of those and larger tracheal rings found detached in different New-Zealand 

 localities to species of the genus Dinornis. 



Of the skulls ascribed to species of the genus, figured in former volumes of our 

 ' Transactions,' that of the present species comes nearest in size and shape, so far as can 

 be determined through the integument, to the subject of figs. 1, 2, & 6 of pi. xiii. of 

 the under-cited volume', referred (p. 139) to Dinornis casuarinus; and, like that skull, 

 the present shows a close resemblance to the skull of the Emu [Drommus novce 

 hollandice), with similar proportions, positions, and relative size of the narial, orbital, 

 and auditory apertures. 



In the transmitted parts of the hind limbs of Dinornis didinus the tibiae and fibulse 

 are bare, the bones of the feet more or less enclosed in their integuments. 



' Trans. Zool. Soc. vol. vii. p. 381. 



" Anatomy of Vertebrates, vol. ji. p. 151, figs. 73-77, 



^ Trans. Zool. Soc. vol. vii. (1870). 



