DEVELOPMENT OF THE SKULL IN THE BATRACHIA. 
o / 
and 3, sq.), for the descending position of the post-orbital process, and for the bifurca¬ 
tion of the suprateniporal plate, embracing the “ pterotic ” cartilage. 
The quadrato-jugal (q.j.) grafts itself very little ; the maxillary (mx.) has a very 
distinct ascending facial process below the nasal; it does not, however, articulate 
directly with that bone, for there is a small squarish pre-orbital ( p.ob .) between them. 
Behind this (Plate 8, figs. 1 and 3, l.) there is an oblong bone, also attached to 
the descending crus of the nasal (n.); this is the “ anterior suborbital ” or lacryinal; 
this is a familiar bone in the Teleostei, and the other is common in one “ Family ” 
of that “ Order,” namely, the “ Siluroidei.” 
But these are not all the prater-normal ossicles ; there is no functional septo- 
m ax illar y, as in R. temporaria, where it lines the nasal passage, but there are a number 
of generalised bony points close to where that bone appears, below, in the Common 
Frog. On the left side (Plate 8, fig. 2, and Plate 9, fig. 7, p.mx.) these are close to 
th e palatal junction of the pre-maxillaries and maxillaries, some larger, and others lesser, 
palato-maxillarieson the right side (Plate 8, fig. 2) there are two narrow bones, 
larger than the largest on the left side. 
These do not make up the whole tale of the additional hones ; the parasphenoid 
(Plate 8, fig. 2, pa.s .) has at its apex a separate “ pro-parasphenoid ( pa.s'.) as I showed 
in the larva of this species (Plate 3). This bone is about a quarter the size of the 
blade of the large bone, which is split where it underlies the new centre. 
The vomers (fig. 2, v.) are large and quadrilobate, yet they neither meet at the mid¬ 
line nor reach near to the maxillaries ; for the nasal region, although large really is 
small relatively to the huge face. The fourth or dentigerous lobe of each vomer is 
rounded, the two intermediate lobes that enclose the inner nostril are sharp, and the 
front lobe is crescentic. 
Above (figs. 1 and 3, n.) the nasals are broad, roughly convex, in contact in their 
hinder part, do not reach the maxillaries externally, and together form a sub-pentagonal 
roof. Between them, behind, there is an emargination which passes into the notch 
between the fronto-parietals ( f.p.) and exposes some of the girdle-bone ( eth .), whose 
superorbital lobe ( s.ob .) is also uncovered externally. 
The frontals are not confluent with each other, but with the parietals ; these are 
completely anchylosed together (fig. I, f.p.). 
The sides of this roof are almost parallel for two-thirds of the interorbital region ; then 
the bones suddenly widen, then become pinched and bi-cristate, and then double their 
breadth over the inter-auditory region, where their outer margin is emarginate, and 
their surface sinuous over the double “ canal.” The two crests are divided by a fossa ; 
they are first temporal, and then sagittal. 
This compound roof ends, behind, in a transverse, dentate, squamous edge, leaving 
the narrow superoccipital region uncovered. Laterally (fig. 3), the bony roof and the 
bony floor are seen to be modelled over and around the endocranium, hiding half 
of it. 
MDCCCLXXXT. 
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