513 



in the premaxillary, as they are below or in front of the 

 nasal aperture. The form of the teeth, both crown and 

 root, is very similar to the teeth of Hesperornis. The 

 fact that some teeth are scattered about near the jaw 

 would suggest that they were implanted in a groove. 

 No teeth are known lrom the lower jaw, but they were 

 probably present. 



The presacral vertebrae are all, or nearly all, biconcave, 

 resembling those of Ichthyornis in general form, but 

 without the large lateral foramina. There appear to be 

 twenty-one presacral vertebrae, and the same, or nearly 

 the same, number of caudals. The sacral vertebrae are 

 fewer in number than in any known bird, those united 

 together not exceeding five, and probably less. 



The scapular arch strongly resembles that of modern 

 birds. The articulation of the scapula and coracoid, and 

 the latter with the sternum is characteristic ; and the fur- 

 culum is distinctly avian. The sternum is a single broad 

 plate, well ossified. It probably supported a keel, but 

 this is not exposed in the known specimens. 



In the wing itself the main interest centres in the 

 manus and its free metacarpals. In form and position 

 these three bones are just what may be seen in some 

 young birds of to-day. This is an important point, as it 

 has been claimed that the hand of Archceopteryx is not 

 at all avian, but reptilian. The bones of the reptile are 

 indeed there, but they have already received the stamp of 

 the bird. 



One of the most interesting points determined during 

 my investigation of Archceopteryx was the separate con- 

 dition of the pelvic bones. In all other known adult 

 birds, recent and extinct, the three pelvic elements, ilium, 

 ischium and pubis, are firmly anchylosed. In young 

 birds these bones are separate, and in all known Dino- 

 saurian reptiles they are also distinct. This point may 

 perhaps be made clearer by referring to the two diagrams 

 before you, which I owe to the kindness of my friend Dr. 

 Woodward, of the Britism Museum, who also gave me 

 excellent facilities for examining the Archceopteryx under 

 his care. In the first diagram we have represented the 

 pelvis of an American Jurassic Dinosaur allied to Iguan- 

 odon, and here the pelvic bones are distinct. The second 

 diagram is an enlarged view of the pelvis of the Archie- 

 opteryx in the British Museum, and here too the ilium is 

 seen separate from the ischium and pubis. 



In birds the fibula is usually incomplete below, but it 

 may be coossified with the side of the tibia. In the typical 

 Dinosaurs, Iguanodon, for example, the fibula at its distal 

 end stands in front of the tibia, and this is exactly its 

 position in Archceopteryx, an interesting point not before 

 seen in birds. 



The metatarsal bones of Archceopteryx show, on the 

 outer face at least, deep grooves between the three ele- 

 ments, which imply that the latter are distinct, or unite 

 late together. The free metacarpal and separate pelvic 

 bones would also suggest distinct metatarsals, although 

 they naturally would be placed closely together, so as to 

 appear connate. 



Among other points of interest in Archceoptcyx may 

 be mentioned the brain-cast, which shows that the brain, 

 although comparatively small, was like that of a bird, 

 and not that of a Dinosaurian reptile. It resembles in 

 form the brain-cast of Laopteryx, an American Jurassic 

 bird, which I have recently described. The brain of both 

 these birds appears to have been of a somewhat higher 

 grade than that of Hesperornis, but this may have been 

 due to the fact that the latter was an aquatic form, while 

 the Jurassic species were land birds. 



As the Dinosauria are now generally considered the 

 nearest allies to Birds, it was interesting to find in those 

 investigated many points of resemblance to the latter class. 

 Co?npsognathus, for example, shows in its extremities a 

 striking similarity to Archceopteryx. The three clawed 

 digits of the manus correspond closely with those of that 

 genus ; although the bones are of different proportions. 



The hind feet also have essentially the same structure in 

 both. The vertebras, however, and the pelvic bones of 

 Compsognath us differ materially from those of Archceop- 

 teryx, and the two forms are in reality widely separated. 

 While examining the Compsognathus skeleton, I detected 

 in the abdominal cavity the remains of a small reptile 

 which had not been previously observed. The size and 

 position of this inclosed skeleton would imply that it was 

 a fcetus ; but it may possibly have been the young of the 

 same species, or an allied form, that had been swallowed. 

 No similar instance is known among the Dinosaurs. 



A point of resemblance of some importance between 

 Birds and Dinosaurs is the clavicle. All birds have these 

 bones, but they have been considered wanting in Dino- 

 saurs. Two specimens of Iguanodon, in the British Mu- 

 seum, however, show that these elements of the pectoral 

 arch were present in that genus, and in a diagram before 

 you one of these bones is represented. Some other Di- 

 nosauria possess clavicles, but in several families of this 

 subclass, as I regard it, thev appear to be wanting. 



The nearest approach to Birds now known would seem 

 to be in the very small Dinosaurs from the American Ju- 

 rassic. In some of these the separate bones of the skel- 

 eton cannot be distinguished with certainty from those of 

 Jurassic Birds, if the skull is wanting, and even in this 

 part the resemblance is striking. Some of these diminu- 

 tive Dinosaurs were perhaps arboreal in habit, and the 

 difference between them and the Birds that lived with 

 them may have been at first mainly one of feathers, as I 

 have shown in my Memoir on the Odontornithcs, pub- 

 lished during the past year. 



It is an interesting fact that all the Jurassic birds 

 known, both from Europe and America, are land birds, 

 while all from the Cretaceous are aquatic forms. The 

 four oldest known birds, moreover, differ more widely 

 from each other than do any two recent birds. These 

 facts show that we may hope for most important discov- 

 eries in the future, especially from theTriassic, which has 

 as yet furnished no authentic trace of birds. For the 

 primitive forms of this class we must evidently look to 

 the Palaeozoic. 



THE LIMITED BIOLOGICAL IMPORTANCE OF 

 SYNTHETIC ACHIEVEMENTS IN ORGANIC 

 CHEMISTRY.* 



By Professor Albert B. Prescott. 



The solicitude shown for half a century as to the bio- 

 logical import of chemical synthesis arises from a misap- 

 prehension of the scope of chemical action. From all 

 we know of chemism, it must be accepted, (i) that all 

 the matter of protoplasm and cell is carried strictly in a 

 state of chemical combination, but (2) it cannot therefore 

 be accepted that chemical composition supplies the essen- 

 tial conditions or impulses for organization or other vital 

 functions. The synthesis of all the chemical compounds 

 of the living body may or may not be attainable in the 

 laboratory, but its success would give no whit of promise 

 for the development of organization. Chemical action is 

 distinct from cell organization as it is from heat, cohesion, 

 etc., and its corelations with all these forces have to 

 await demonstration by experiment. Cell growth ap- 

 pears to be a necessary factor in the simple splitting of 

 sugar into alcohol and carbon dioxide, and it may or may 

 not be an essential factor in the chemical synthesis of 

 proteids or of cellulose. 



A gentleman of Milan, Signor Lorin, deserves high 

 credit, for the public spirit of philanthropy he has shown 

 in offering 20,000 francs to the municipal authorities to 

 maintain a mortuary and post mortem room wherein the 

 bodies of all persons dying of unexplained causes shall 

 be rigidly examined before they are cremated. 



* Read before the A. A. A. S., Cincinnati, 1881. 



