Page:Encyclopædia Britannica, Ninth Edition, v. 3.djvu/746

Rh 728 The integument of Birds is, for the most part, devoid of glands ; but many Birds have a peculiar sebaceous gland developed in the integument which covers the coccyx. This uropygial gland secretes an oily fluid, which the Bird spreads over its feathers by the operation of &quot; preening.&quot; The excretion passes out by one or two apertures, commonly situated upon an elevation, which may or may not be provided with a special circlet of feathers. In various Birds (e.g., the Turkey) the integument about the head and neck develops highly vascular and sometimes erectile processes (combs, u attles). Within the extremely narrow space of an article like the present, the merest abstract of most of our present orni- thotomical knowledge can be given. A mere list of the published works on the subject would fill most of the space allotted to the writer. We will conclude by giving Professor Huxley s masterly comparison of the Bird class, and that of the Reptiles below with the Mammalia above them (see Proc. Zool. Soc., April 11, 1867). The writer has modified some assertions from later papers by the same author : &quot; That the association of Birds with Reptiles into one primary group of the Verlebrata, the SAUROPSIDA, is not a mere fancy, but that the necessity of such a step is as plain and demonstrable as any position of taxonomy can be, appears to me to be proved by an enumeration of the principal points in which Avcs and Rcptilia agree with one another and difl er from the Mammalia. &quot;1. They are devoid of hair. &quot; 2. The centra of their vertebra have no epiphyses. &quot; 3. Their skulls have single occipital condyles. &quot; 4. The prootic bone either remains distinct throughout life, or unites with the epiotic and opisthotic after these have become ankylosed with the supra-occipital and exoccipital. &quot;5. The malleus is not subservient to the function of hearing, as [one of the] ossicula auditus. &quot;6. The mandible is connected with the skull by the intermedia tion of a quadrate bone [which represents the upper bulbous part, with the manubrium of the malleus of Mammalia]. &quot;7. Each ramus of the mandible is composed of a number of separate ossifications, which may amount to as many as six in all. (Of these the articularc represents the [antero-inferior part of the] malleus of Mammalia). &quot;8. The apparent ankle-joint is situated not between the tibia and the astragalus, as in the Mammalia, but between the proximal and distal divisions of the tarsus, 1 &quot; 9. The brain is devoid of any corpus callosum. &quot;10. The heart is usually provided with two aortic arches ; if only one remains, it is the right. &quot; 11. The red blood-corpuscles are oval and nucleated. &quot;12. The cavities of the thorax and abdomen are never separated by a complete diaphragm. &quot; 13. The allantois, which is highly vascular, is very large, and envelops the embryo ; but no villi for placental connection with the parent are developed upon it. &quot; 14. There are no mammary glands.&quot; (W. K. P.) FOSSIL BIRDS. posed Footprints, or casts of footprints, at the time of their sic discovery and long afterwards supposed to be those of Birds, were found about the year 1835 in the Triassic forma tion of the valley of the Connecticut in New England, and were described by Messrs Deane and Marsh. Subsequently Professor Hitchcock and Mr Warren contributed to the elucidation of these tracks, which were ascribed to various genera of the Class that received the names of Amblonyx, Argozoum, Brontozoum, Grallator, Ornithopus, Platypterna. Tridentipes, and others. No portion of any of the animals to which these traces are due seems to have been met with, 2 1 See Gegenbaur, Archiv fur Anatomic (1863), and Untersuchungen zur vergleichenden Anatomic (1864). - The only known bones from this deposit were exhibited by Pro fessor W. B. Rogers at the meeting of the British Association in Bath (Rep. Br. Ass. 1864, Trans. Soft., p. 66). [FOSSIL FOEMS. and the best American palaeontologists are now inclined to attribute them rather to Dinosaurian Reptiles than to Birds. Whatever may be throught of the rest, it appears moet likely that the creatures designated as Platypterna and Tridentipes were certainly not ornithic. Brontozoum must have been a colossal animal, its footprint measuring about 1C| inches in length and its stride some 8 feet. An enormous space of time separates these reputed Oolitic Ornithichnites, as they are called, from the first undoubted Birds, fossil Bird. This was discovered in 1861 by Andreas Wagner in the lithographic slate of Solenhofen in Bavaria, belonging to the Oolitic series, and is commonly known by the name of Archceopteryx? though that of Grypliosaurus FIG. 38. Slab containing remains of Archccopteryx, from the original in tha British Museum. Reduced. was given by its original describer to the at present unique specimen now in the British Museum. Unfortunately deficient in some very important parts such as the head and nearly all the sternal apparatus it has others in ex cellent preservation. It was about the size of a Rook (Corvus frugilegus), and along with the greater portion of the skeleton, impressions of many of its feathers, parti cularly the quills, are plainly visible. Its most obvious peculiarity is the presence of a long Lizard-like tail, com posed of twenty vertebra ; but from each of these springs a pair of well-developed rectrices. A scarcely less remark able feature is that afforded by the extremity of the wings, where it would appear that there was a free digit answering to the pollex. The many Reptilian characters of this wonder ful creature cannot be noticed in this treatise, though their value must be fully admitted; but since the appearance of Professor Owen s description of the specimen (Phil. Trans. 1863, p. 33), nobody has hesitated to receive it as a true Bird, though one which exhibits an extraordinary dis similarity from all other known members of the Class. To make any suggestion as to the more immediate affinities and habits of Archceopteryx were vain. It at present 3 Herr Hermann von Meyer had previously described a fossil feather from the same formation, to the owner of which he gave this name. Its specific, generic, not to say ordinal, identity with the creature whose remains were subsequently found is of course problematical, but thn received laws of nomenclature fully justify the common usage.