70 PROF. G. B. HOWES AND MR. H. H. SWINNERTON ON THE 
applying to the former condition the term Archicraniate', and to the latter that of the 
Syncraniate. 
The characters of the occipital condyle and the presence of one, two, or, for the 
matter of that, of three condyles, no longer have the significance once attached to them 
as criteria of affinity. 
Judged from this point of view, the Rhynchocephalia may well be regarded as a 
lowly group, ancestral to the Sauropsida as ordinarily defined, and intimately related 
to the Anomodontia; and while the latter, perhaps with or through the Pelycosauria of 
Cope, on the one hand gave rise to the Mammalia, they were probably with the Rhyn- 
chocephalia derived by diversity of modification from some common ancestral stock 
which carries us towards a group which must have been either Batrachian Reptiles or 
Reptilian Batrachians, as compared with forms extant—/. ¢., they either possessed a 
coraco-sternum and an archicranium, or a costal-sternum and a syncranium, structural 
combinations which go hand in hand. If they were of the latter type, the living 
Batrachia must have suffered the loss of a costal-sternum and not a few of their 
distinctive characters must be indicative of retrogression. The argument applies 
equally to the quadrate and whether its representative in the living Batrachia is or is 
not vestigial, and, as concerning the parasphenoid and pterygoids, the question arises 
whether in these ancestral forms they did or did not reach the vomers. 
On the other hand, it is possible that, in some manner yet to be discovered, the 
ancestral series of Terrestrial Vertebrata may have combined the characters of the later 
differentiated forms, as Gadow has surmised in his sagacious remark? that ‘the 
Amphibia and Reptiles do not form a continuous line of development, but are two 
divergent branches of a common stock of Paleozoic Tetrapoda.” If, with Credner, we 
group together the Stegocephalia and “ Proganosauria” as the “ Kotetrapoda” *, or with 
Dawson and Baur?‘ associate a no less heterogeneous assemblage under the cognomen 
“ Microsauria,” we but imply the conviction herein set forth. 
Concerning the phalangeal problem, the discovery that certain living Chelonia are 
hyperphalangeata®; that by Peters ® that in the Pleurodian Pelomedusa the numerical 
reduction of the phalanges is in part due to fusion of more numerous elements during 
' Sewertzoff writes (Bull. Soc. Nat. Mosc. n. s. vol. ix. 1895, p. 186): “ Bei die Amphibien entspricht der 
Ganze Occipitalabschnitt einem einzigen Segmente, dein einfachen Occipitalbogen, so dass die Amphibien in 
dieser Hinsicht unter allen Cranioten, mit Ausnahme der Petromyzonten, die einfachsten Zustand zeigen.” 
Intensely interesting in this association are the recent observations of Peter (op. cit. [antea, p. 50] pp. 590- 
592), based on the discovery in Ichthyophis of a postvagal nerve, having, it would seem, an essential similarity 
to the “spinal accessory ” of the Amniota. 
* Gadow, H.: Phil. Trans. vol. 187. 1896, p. 23. 
3 Oredner, H.: Allgem, Verstell. naturwiss. Abhandlg. Berlin, Hft. xv. 1891 (‘ Naturwiss. Wochenschr.”’), 
pp. 1-52. 
* Cf. Baur,G.: Anat. Anz, Bd. xiv. 1897, p. 148, and Bd. xi, 1896, p. 657. 
* Cf. Boulenger, G. A.: Brit. Mus. Cat. Chelonians, 1889, p. 240, espec. Chitra. 
° Peters, W.: Reise nach Mossambique, Zool. iii. Berlin, 1882, p. 6. 
