﻿KIMMERTDGE CLAY. 



75 



In the lecture " On the Animals which are most nearly Intermediate between Birds 

 and Reptiles," delivered by Professor Huxley at the Royal Institution of Great Britain, 

 7th February, 1868, he states: — "I hold it to be certain that these bones — the so- 

 called ' clavicles n — belong to the pelvis and not to the shoulder-girdle, and I think it 

 probable that they are ischia ; but I do not deny that they may be pubes." 



Thanks to the rapidity by which, through science, sea and land can now be traversed, 

 we get the results of research by our American fellow-labourers within a fortnight, usually, 

 after publication. 



I have no doubt of the legitimacy of Professor Huxley's assertion — " I could not 

 possibly have known anything about them when my ' Lecture' was delivered ;" but 

 the originality of his views of problematical pelvic bones by no means called for any 

 reflection on postal arrangements between Great Britain and the United States. The 

 impossibility might merely mean an oversight which left the writer ignorant of both 

 Cope's and Leidy's anticipations, as appears to have been the case with regard to von 

 Meyer's paper in the ' Isis' of 1830. 



In the "Further Evidence of the Affinity between the Dinosaurian Reptiles and 

 Birds," with confirmatory testimony by Professor Phillips, of Oxford, 2 Professor Huxley 

 adopts the ischial homology of the bone in question, and illustrates it by a diagram, 

 "Fig. 3, Dmosaur," p. 27 (torn, cit.), in which the supposed " ischium" is directed from 

 the acetabulum downward and backward, parallel with the pubis, with which it articu- 

 lates by the process (c, figs. 4 and 5, in Plate XX, " Omosaurus"), so as to " interrupt the 

 obturator space," and define, as in Birds, an anterior part of that space as an " obturator 

 foramen " (loc. cit.). 



To an advocate of the affinity of Dinosaurs to Birds and of the derivation of Birds 

 from Dinosaurs, such determination of the bone in question gave great help, and the 

 consequent diagram has been mainly subservient in gaining suffrages to the idea — I may 

 term it sensational — of the kinship of the Iguanodon with the Cassowary, carried to the 

 inference of a common bipedal mode of progression. 



The value of the genus Omosaurus, as of every well-determined new Dinosaur, to the 

 Pala?ontologist desirous, irrespective of foregone conclusions, to lay the basis of lasting 

 views of affinity on fixed homologies, is here great. The bone, PI. XIX, 63, which com- 

 pletes the acetabulum, shows by the extent and position of its articulation with the ilium, 

 from which it has been but slightly dislocated, that it is the ischium. The recovery of 

 the parial bone to the extent shown in PI. XX, fig. 1, shows that the shaft gives off no 

 process ; also that an extension of the iliac articular end beyond the acetabular surface of 

 the ischium, and behind it, is the sole production, transverse to the axis of the bone, which 

 can be homologised with a non-articular process in the ischia of other Vertebrates. 



1 Erroneously so called in my ' History of British Fossil Reptiles,' part v, p. 265, 4to, 1851. 

 3 'Quarterly Journal,' &c, torn, cit., p. 12. 



