Owen—New Reptile from the Coal. ts 
anastomosing and causing the reticulo-striate and divergent impres- 
sions characteristic of Ganocephalous and Labyrinthodont cranial 
bones; cut, fig. 2. The expanded end of a long bone, PI. I. fig. 8, has 
not terminated in a smooth, well-ossified surface supporting articular 
cartilage for a synovial joint, but 
has terminated, like some limb- 
bones in existing Perennibran- 
chiate Batrachians, in unossified 
fibro-cartilage, showing in its pre- 
sent state the matrix in a finely 
granular state, surrounded by a 
thin film of bone: this rapidly 
thickens as the articular surface 
contracts into the shaft, where, 
at the point of fracture, a small 
subcentral unossified tract is ex- _‘ Fig. 2. Part of cranial bone (PI. I. fig. 3) ; 
magnified. 
posed. 
The portion of bone fig. 9 indicates a similar incompletely ossified 
condition of the articular expansion; where, however, the thin outer 
crust of bone is continued from the periphery across the short 
diameter, leaving or marking out two unossified spaces filled by 
matrix, and which I infer, from Batrachian analogies, to have 
originally contained unossified cartilage. The side of the bone is 
longitudinally impressed, indicating the coalescence or connation of 
a pair of bones, and the fracture of the shaft, as in that of the con- 
nate tibia and fibula of the Frog, shows the confluence of the two 
unossified tracts into one, simulating a medullary cavity. The frac- 
tured ends of the other long and slender bones are remarkable for 
the contracted area of the corresponding cavity, and for the density 
and thickness of the surrounding bony wall. 
Such a section is figured, magnified 50 diameters, in Pl. II. fig. 1; 
and microscopical evidence of the Batrachian character of the 
bone is given in fig. 2, longitudinal section, and fig. 3, transverse 
section, of the ‘ bone-cells,’ magnified 222 diameters. 
In both size and shape these bone-cells closely correspond with 
those of Baphetes planiceps, from the Pictou Coal, Nova Scotia. . 
The present portions of the skeleton of the air-breather from 
the Welsh Coal indicate a species intermediate in size between 
Baphetes planiceps and Dendrerpeton Acadianum. The ribs 
were longer than they are known to be in any Labyrinthodont; 
and they were better developed in that extinct group than they 
are in Ganocephalans or in modern Batrachians. 
The structure of these long and slender bones, as of the 
thicker limb-bones, shows that the cavity was not truly medul- 
lary, but had been occupied by unossified chondrine, as in 
perennibranchiate Batrachia, and in the bones of many Fishes 
that are hollow after maceration, and show in the fossil state 
cavities, like medullary spaces, occupied by matrix. 
