76 SCIENTIFIC AND LITERARY NOTES. 
to test the hypothesis of the Apateon being a fossil fish, he has sent to Agassiz a 
drawing, with a description of it.” Three years later, better preserved and more 
instructive specimens of the problematical f ssil were obtained by Prof. von 
Dechen from the Bavarian coal-fields, and were submitted to the examination of 
Prof. Goldfuss, of Bonn; he published a quarto memoir on them, with good 
figures, referring them to a Saurian genus, which he calls Archegosaurus, or 
‘* primeval lizard,”—deeming it to be a transitional type between the fish-like Ba- 
trachia and the lizards and ecrocodiles.* The estimable author, on the occasion of 
publishing the above memoir, transmitted to Prof. Owen excellent casts of the 
originals therein described and figured. These casts were presented by the Pro- 
fessor to the Museum of the Royal College of Surgeons, London, and were 
deseribed by him in his ‘ Catalogue of the Fossil Reptiles,’ in that Museum, (4to. 
1854), The conclusions which Prof. Owen formed thereupou, as to the position 
and affinities of the Archegosaurus in the reptilian class, are published in that 
Catalogue, and were communicated to and discussed at the Geological Society of 
London (see the ‘Quarterly Journal of the Geological Society, Vol. iv., 1848). 
One of the specimens appeared to present evidence of persistent branchial arches. 
The osseous structure of the skull, especially of the orbits, through the completed 
zygomatic arches, indicated an affinity to the Labyrinthodonts; but the vertebree 
and numerous very short ribs, with the indications of stunted swimming limbs, 
impressed the writer with the conviction of the near alliance of the Archegosaurus 
with the Proteus and other perennibranchiate reptiles. This conclusion of the 
affinity of Archegosaurus to existing types of the reptilian class is confirmed by 
the subsequently discovered specimens described and figured by M. von Meyer, in 
his ‘ Paleeontographica’ (Bd. vi., 2te Hef. 1857),—more especially by his discovery 
of the embryonal condition of the vertebral column+—z. ¢., of the persistence of 
the notochord, and the restriction of ossification to the arches and peripheral 
vertebral elements. In thisstructure the old carboriferous Reptile resembled the 
existing Lepidosiren, and afforded further ground for regarding that remarkable 
existing animal as one which obliterates the line of demarcation between the fishes 
and the reptiles. Coincident with this non-ossified state of the basis of the verte- 
brate bodies of the trunk is the absence of the ossified occipital condyles, which 
condyles characterize the skull in better developed Batrachia. The fore part of 
the notochord has extended into the basi-sphenoid region, and its capsule has con- 
nected it, by ligament, to the broad, flat ossifications of expansions of the same 
capsule, forming the basi-occipital or basi-spbenoid plate. The vertebre of the 
trunk in the fully developed full-sized animal present the following stages of 
ossification, The neurapophyses coalesce at the top to form the arch, from the 
summit of which was developed a compressed, subquadrate, moderately high 
spine, with the truneate, or slightly convex, summit, expanded in the fore-and aft 
direction, so as to touch the contiguous spines in the back: the spines are distinct 
in the tail. The sides of the base of the neural arch are thickened and extended 
outwards into diapophyses, having a convex articular surface for the attachment 
* “ Avchegosaurus: Fossile Saurier aus dem Steinkohlengebirge die den Uebergang des 
Ichthyoden zu den Lacerten und Krokodilen bilden,” p. 3. ‘Beitrage zur vorweltlichen 
Fauna des Steinkohlengebirges,’ 4to. 1847, 
+*Reptilien ausder Steinkohlen Formation in Deutschland,’ Sechster Band, p. 61. 
