PROFESSOR OWEN ON THE GENUS DINORNIS. 365 
compare therewith the muscles in a fowl answering to those called rectus capitis anticus 
major (Zool. Trans. vol. iii. p. 285, pl. 35, )), rectus cap. ant. minor (ib. p. 286, pl. 35, ¢), 
rectus cap. lateralis (ib. pls. 32 & 35, d), biventer capitis (ib. p. 284, pl. 33, o**), com- 
plexus (ib. pls. 32 & 34, y), and trachelo-mastoideus (ib. pl. 34. fig. 1, 7). The develop- 
ments of cranial bone for the insertions of the corresponding muscles in Aptornis indicate 
a fourfold increase of force and size, and bespeak corresponding power with which the 
beak was driven through the surface and the soil displaced. For this application it 
was requisite that the lower jaw should be held firmly in contact with the upper one, 
that both might penetrate as one instrument with a common sharp-edged extremity ; 
hence the evidence of unusual extensions from the main cranial diapophyses of the 
bony processes giving origins to the muscles working the cranial rib, 7. e. drawing up 
the mandible and holding it in close contact with the maxilla, as in that action of the 
corresponding muscles of the strong man who in a determined and vigorous effort sets 
his teeth. 
Underlying all these exaggerations of apophysial outstandings, we nevertheless dis- 
cern a “porphyrian platform’—so much more essential resemblance to the cranial 
characteristics of the Coots, especially the larger kinds, whose craniology is illustrated 
in plate 56 of the third volume of the Transactions of the Society, as to conclude 
Aptornis to have been (if one may not speak of it as present in the living creation) a 
gigantic modified * Ralline.” The down-bending of the mandible, it is true, is not seen 
in Notornis or Porphyrio; but in the “ Poule rouge au bec de Bécasse” of the Mascarene 
Islands (for a knowledge of which we are indebted to Von Frauenfeld’s publication of 
the coloured drawing, from the life, preserved in the library of the Emperor Francis I.) 
one sees a curve of beak like that of Aptornis. The mandible of this probably extinct 
Mauritian bird, which has been obtained, with bones of the Dodo, from the famous 
“‘Mare aux Songes,” shows also, in the figures given by M. Alphonse Milne-Edwards’, 
the deflected angle answering to 30 in Porphyrio (fig. 1. pl. 56, Trans. Zool. Soc. vol. iii.) 
and Notornis (ib. fig. 7), also the small “ prearticular foramen” (ib. ib. figs. 1 & 7, 10). 
The larger vacuity (ib. ib. uw) is almost reduced to the state of obsolescence which cha- 
racterizes the more consolidated and more powerful mandible of Aptornis (comp. fig. 4 
with the mandible in fig. 1, Pl. XL.). The extent of symphysis, with its canaliculate 
upper surface, is interestingly similar in Aphanapteryx (Pl. XLI. fig. 5) and Aptornis 
(ib. fig. 6); and I concur in the conclusions to which M. A. Milne-Edwards has been 
led as to the “analogies of Aphanapterya with the Rails”*. In speculating on the 
* « Researches into the Zoological Affinities of Aphanapteryx,” in Ibis for July 1869. 
? This, 1869, p. 267. By a curious coincidence, at a later period of the year (1848) in which I proposed a 
diminutive of “ Apterygiornis” for the large extinct Coot of New Zealand, the accomplished Belgian orni- 
thologist, M. de Selys-Longchamps, was moyed to propound a minor diminutive of the same term for some 
loosely indicated Mascarene birds, one of which we now know to have been an extinct Coot of the Mauritius. 
Without entering into the question of the degree of synonymy of Aptornis and Apterornis, the priority of pro- 
position of the first will, I apprehend, secure it for the main subject of my present Memoir. 
