Jávorka Sándor - Soós Lajos (szerk.): A Magyar Természettudományi Múzeum évkönyve 29. (Budapest 1935)
Fejérváry, G. J.: Further contributions to a monograph of the Megalanidae and fossil Varanidae - with notes on recent Varanians
they are rather weak, indeed, if they are compared to the considerable bulk of the whole vertebra. With respect to this proportion I should like to refer to another one, paralleling it, as offered in the relation existing between the size of the neural aperture and canal, respectively, and the dimensions of the vertebra itself. I have already pointed out, in my Monograph previously cited, the extreme smallness of the neural canal in Megalania, 52 a feature proving the predominance of the skeletal system upon the nervous one, and characteristic of many a fossil representative of the Reptilian Order. 5 "' Very like this hypo-development of the spinal canal, we notice an „underdevelopment" of the zygospheno-zygantral structure, which might, somehow, even be dependent on, or rather causally related to, the special vertebral mechanism arisen by means of the hypertrophy of both the neural arch and centrum on the one hand, and the reduction of the neural canal on the other. For, in the course of Reptilian phylogeny, the neural canal, which was originally of an average size, has first undergone a process of reduction, to be, afterwards, secondarily increased. And inversely the same course of evolution was followed by the bony tissue's mass, consisting in an originally moderately developed centre and arch, gradually augmenting in bulk, to be again weakened in the modern offshoots. We must not forget that the zygospheno-zygantral articulation determines, in a very definite way, the kinetomechanism of the vertebral column, and that the bulk and the lumen of the vertebrae are most important determiners in their bearing upon the actions of animal movement in general, and upon the development of vertebral detail structures in particular. So it 'will surely not be indifferent to the formation of a zygosphene and zygantrum, whether the vertebra concerned is of a great bulk and provided with a small spinal canal, or if it is, on the contrary, light-built and presenting a spacious lumen. I do not think, however that there is any correlation obtaining between the formation of a zygospheno-zygantral articulation and the degree of spaciousness of the spinal canal — I do merely believe that the special type of the former may be very much dependent on the latter. That means my supposing the existence of a relation between the two structural peculiarities mentioned, viz. of a one52 Op. cit. p. 455 & 460. 53 Cfr. Dr. Baronin A. M. v. F EJÍRVÁRY—LÁNGH, Beitr. z. einer Monogr. d. fossilen Ophisaurier, Palaeont. Hungar., 1, 1921—1925, 1923, p. 215—216.
