188 MR. W. K. PARKER ON STEATORNIS CARIPENSIS. [Apr. 2, 



aa 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 rypical 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 leaveu 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 

 vertebrae has its articulations of the opisthocoelian 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 OrnithosceliJan 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 Ratitae and Carinatse, 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 Cariuatse, — Muso- 

 pbagidse, Procellariidae, &c., — has in its fore palate the triradiate 

 remnant of the fore part of tlie 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 "Arnniota" — 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 becoming 

 hot-blooded, quick-tempered, intelligent, vt-cal, 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 larvae 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, bi/ the mystery of transformation, the Reptiles and Birds 

 bad 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 in a 



