644 
ME. W. K. PAEIvEE ON THE STEUCTUEE AND 
figs. 3 & 4), by proper segmentation of the cartilage, but because the pterygoid cartilage 
is used up by the bone ; whereas the palatine is quite unossified, it has no ectosteal bar, 
and merely shows some calcification where it is set on to the ethmoid ( e.pa .). At pre- 
sent this is the only Batrachian in which I miss the ectosteal palatine bar. 
The free mandible has an oblique, sinuously convex condyle, accurately surrounded 
by the articular bony plate (Plate 58. fig. 6, and Plate 59. fig. 3, ar .) ; this is the angular 
(An.) of Huxley. This bone has transformed most of the cartilage, but in front it 
breaks out again, and shows no distal ossicle (“ mento-Meckelian ”), but, reaching to 
near its end, and running along the outside as a spinous splint, we have the dentary 
(d.) ; it is two thirds the length of the mandible. On the inner side (Plate 58. fig. 6, ar.) 
the articular ends in a spike, at a small distance from the fibrous symphysis. 
In the hyoid arch the antero-superior element has appeared, which we saw not in the 
last stage (Plate 58. fig. 3), only a cerato-hyal being there present ; but the stapes already, 
for several stages, had been perfect. 
If we creep along cautiously, without taking thought either for function or for what 
shall be seen in higher types, it will not be hard to find that here, late in life, has 
appeared the lacking upper segment of the “ 2nd postoral arch.” Holding in mind 
what is familiar in the various groups of fishes, this new part may be considered as the 
homologue of the hyomandibular and symplectic of the Osseous Fish (“ Salmon’s Skull,” 
var. loc., lun ., sy.), the proximal bone being the hyomandibular, and the distal, with its 
free cartilaginous extremity, the symplectic*. 
But I gladly use Professor Huxley’s tympanic nomenclature for this upper bar, this 
hyostapedial chain. 
The “ columella ” of Dactylethra (Plate 59. figs. 1, 2, 3, 4, 7) is bufonine (see Plate 54. 
figs. 7 & 8), and does not agree with that of the Frogs (“ Frog’s Skull,” plate viii. 
figs. 8 & 9). In the Toads there is no separation into two distinct segments of the pri- 
mary cartilaginous bar (Plate 54. fig. 8, co.); but the more rounded proximal part, the 
stalk , is ossified as two separate shaft-bones, the proximal end of the proximal piece 
articulating with the stapes (fig. 7, st.). 
The curve which has to be formed by the columella (figs. 1, 2, 3, 4), as it stands out 
from the stapes, which is set in the postero-superior face of the outspread ear-capsules, 
is evidently at the bottom of this peculiar segmentation. 
The upper piece, or “ interstapedial ” (it.st.), is bent on itself ; the second piece, or 
“ mediostapedial ” (m.st.), is bent on it ; and this bar also is bent on itself, but gently, 
in an arcuate manner. 
This curvature is still contained in the leaf (see from the inside, fig. 7, e.st.), which is 
applied over the outer face of the squamosal, quadrato -jugal, and quadrate, reaching 
further forwards than the fore margin of the foramen ovale (figs. 3, 5). The entire 
* If it be asked why the end of the symplectic passes over the quadrate, whereas it was under in the Osseous 
Pish, I answer that they are both secondary morphological positions ; primarily they are serially homologous , 
and should ( and did) simply lie in the same plane. 
