DEVELOPMENT OP THE SKULL IN THE BATRACHIA. 
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in Xenophrys monticola and in Pipa, or its apex may coalesce with the pedicle, as 
in Phyllomedusa and Acris; but as a rule it is confluent above. 
In Callula, Diplopelma, and Engystoma, the basi-hvobranehial plate is sub-carinate 
below, and a basi-branchial bone appears between the thyro-hyals ; in Alytes and 
Pelodytes, a V" shaped splint is applied to this part below. 
In the genus Phryniscus the basal plate is almost as narrow as in Fishes; its 
postero-lateral processes are ossified in Bombinator, and the cerato-hyals have two 
small centres in them on each side, in Pelobates; in the two last, and in some of the 
“ Hylidse,” the front notch is so large as to make the basal plate like two parts 
united by a conjugational band, behind. 
In Hyla rubra and II. Ewingii the basal plate extends, behind, as the rudiment of 
an additional basi-branchial piece. 
The “ investing bones ” show some curious variations in this group. The para- 
sphenoid has a distinct centre, in front, in Rana pipiens and in R. halecina. 
The vomers are absent in Pipa and Hylaplesia; single in Dactylelhra; and confluent 
with the ossified nasal floor in some Phrynisei (e.g., P. cruciger and P. varius) : they 
remain distinct in P. Icevis. 
The fronto-parietals are found right and left, as symmetrical bones, and may divide 
into frontal and parietal for a time; these soon coalesce again, and in many cases the 
median suture is lost; in some cases ( Camariolius tasmaniensis, Acris Pickeringii, and 
Rappia bicolor) they are extremely small. 
The nasals are always present; they are extremely feeble in Dactylethra. 
The septo-maxillaries are very inconstant; in some kinds, as Pipa, Hylaplesia, 
Bufo ornatus, and Rana pipiens, there is a second prse-orbital behind on each side of 
them; in the latter a “ lacrymal ” is also present: in Rana pipiens there is no proper 
septo-maxillary, but several irregular palato-maxillaries. 
The premaxillaries are always double, and the maxillaries nearly always articulate 
with the q-uadrato-jugal to form a perfect cheek bar ; this bar is deficient in the 
“Aglossa” and in Phryniscus Icevis; in Phryniscus the investing bones are very 
unequal, right and left; and in P. varius and P. cruciger the cheek is scarcely 
finished ; the quadrato-jugal is suppressed in Pipa. 
The squamosal is remarkably modified in the Aglossa, being hollowed out to help to 
form the drum-cavity in Pipa and having its lower part aborted in Dactylethra. The 
hollowing out of the squamosal under the “ annulus,” is seen again in Hylaplesia, and 
more or less in many kinds. Its postorbital process is, at times, very short, in others 
very long. 
In Dactylethra, only, have I found any rudiment of the bony “annulus tympanicus,” 
it has two ossicles of this nature on each side; and it only has a single vomer. 
The dentary in the “ Phaneroglossa ” constantly grafts itself on the inferior labial 
after that has become fused with the distal end of the Meckelian rod. 
