188 MR. W. K. PARKER ON STEATORNIS CARIPENSIS. [Apr. 2, 
an essentially Reptilian “root,” yet the various parts are marvellously 
transformed, and the bird itself has gained a tar higher structural 
-and physiological level than that of even the highest and most 
modern Reptile. 
Here, however, in Steatornis, we find the ancient structures built 
up within the modern; it is not a perfectly typical bird, but is com- 
posite, so to speak, a type made of things new and old. 
The Singing-birds, including, of course, the large Crows, have, 
more than any other birds, put away the old leaven of the low 
Reptilian nature that they started with; yet in them, as I have 
shown, the old materials are sometimes built up into, but hidden 
by, the transformed, newer parts. 
But here, in this bird, the hinder part of the pre-sacral chain of 
vertebree has its articulations of the opisthoccelian kind, as in Archaic 
Reptiles. Its palate, also, has just the same degree of Desmogna- 
thism as the Green Turtle (Chelone viridis); and it has more free 
cervical ribs than any other known bird. 
Its tarso-metatarsus is but that of an Ornitkoscelidan Reptile, just 
masked by ankylosis of certain parts; it is in an arrested condition 
as compared with that of any Passerine bird. 
All birds living, both Ratitee and Carinate, come nearer the 
Amphibia than any kind of existing Reptiles in the foundations of 
the cranial superstructures ; the “ parasphenoid”’ is very large and 
Ichthyopsidian in all these supra-reptilian types. 
But the Oil-bird, like a few more of the Carinatee,—Muso- 
phagidee, Procellariide, &c.,—has in its fore palate the triradiate 
remnant of the fore part of the Amphibian palato-quadrate ; it 
clearly shows, in the adult, the “ethmo-,” ‘ pre-,” and “ post- 
palatine ” bars. 
The conclusion to be drawn from facts of this kind is, surely, not 
that Birds are to be imagined as arising from the Reptiles, proper— 
the cold-blooded ‘‘ Amniota”’—either by the utilization of sudden 
“ sports,” or by a slow, secular adaptation of Reptilian structures to 
the necessities of a flying creature, this flying creature bécoming 
hot-blooded, quick-tempered, intelligent, vocal, and loving. 
Rather, it seems to me, to point out that the origin of the Bird 
must be sought for, by the “‘ scientific imagination,” among low and 
quasi-larval forms, similar to those with which we are acquainted in 
the larvee of existing Amphibia and Fishes, and similar to, and near 
relations of, other low Chordata, that gave rise to the Reptiles. 
The low and simple types from which we may suppose the Mam- 
malia to have arisen could not have been so nearly related as those 
from which, by the mystery of transformation, the Reptiles and Birds 
had their origin. 
Although hot-blooded, the lowest kind of Mammals—the Mono- 
tremes—are in some parts of their organization on a level with 
such Archaic Reptiles as the Ichthyosaurus (for example in their 
shoulder-girdle); yet in the formation of their mouth and middle- 
ear they are quite unlike both Reptiles and Birds; and show ina 
