170 
Prof. Owen on a Species of Parrot. 
margin, which is thinned off to an edge, there are, as in the 
Maccaws and Parrots, grooves and foramina for the small 
nerves and vessels of the formative part of the horny beak- 
sheath. 
But the most decisive test of the nature of the present 
fragment is afforded by the characters of the upper or inner 
surface (fig. 2). This, of course, is concave transversely, and 
shows a more regular upcurving of the sides of the gonys 
than the external surface does. It is marked by the curved 
line, convex backward, which, commencing from near the an- 
tero-lateral angles of that surface, extends to a shallow sub- 
circular depression in the posterior third part of the symphysis. 
Fig. 4. 
Upper or inner view of lower jaw, Ara macao (Linn.). 
A pair of minute foramina marks the anterior border of this de¬ 
pression. The curved line, in recent Parrots (fig. 4), marks the 
posterior extent of the thin internal horny plate of the sheath of 
the lower mandible. 
In size the Mauritian Cockatoo, represented by the above- 
described fragment of skeleton, appears to have equalled the 
Hyacinthine and Blue-and-yellow Aras, or Maccaws (figs. 3 and 4), 
and the larger Cockatoos ( Microglossa ) of Australia. Mr. Gould 
