260 
MR. W. K. PARKER ON THE STRUCTURE AND 
ethmo-palatine becomes segmented from the ethmoid, in front, and from the pterygoid 
cartilage, behind ; in B. vulgaris, also, the pedicle does not lose its apes. 
In Bufo ornatus and in Otilophus margaritifer, as also in a Rappia from Lagos, and 
in Diplopehna berdmorei, the “ orbitar process ” is permanent, but small. 
In many kinds the quadrato-jugal bone sets up ossification in the quadrate region, 
often to a considerable extent. In Dactylethra, Pelodytes, and Bombinator there is 
no palatine bone; it is often subdivided into two, often has a sharp crest, and is 
composed of several bones in Rana pipiens, and may be entirely endosteal as in some 
kinds of Diplopelma. There is a mesopterygoid bone in Rana pipiens, and a meta¬ 
pterygoid in several Ranee. 
Except, probably, in some arrested forms, the “ mento-Meckelian” bone is always 
formed in the “ Phaneroglossa,” but is not distinct in the “ Aglossa;” in these latter 
types the endosteal and ectosteal “ articulare ” are completely fused, and ossify the 
articulo-Meckelian cartilage very largely; this takes place, to a less extent, in many 
of the “ Phaneroojossa.” 
© 
The upper hyoid clement or columella is absent in Pseudophryne Bibronii, Phryniscus 
Icevis, Phryniscus varius, and Bombinator igneus; there is a small bony rudiment in 
Pelobates fuscus, and a small unossified rudiment in Rhinoderma Darwinii. 
1 find no trace of an annulus tympanicus in Pelobates, Bombinator, nor in two out of 
three of the species of Phryniscus, viz.: P. Icevis and P. varius; it exists without a 
columella in Pseudophryne Bibronii, and with a rudiment in Rhinoderma. 
In several high kinds, viz.: Rana halecina, R. palustris, Phyllomedusa bicolor, &c\, 
the proximal part of the columella (shaft or “ medio-stapedial”) becomes segmented off 
from the distal (“extra-stapedial”). This is not in conformity with the segmentation 
of a normal branchial arch, or even of the hyoid of Chimcera, where there is a w T ell- 
formed “ pharyngo-hyal ” above the “ epi-hyal.” 
In the Sturgeon this kind of division does take place; the parts are termed in it 
“ hyo-mandibular ” and “ symplectic.” 
But in the last-mentioned type the pliaryngo-branchials themselves are in two 
segments.* 
I find that in about half of the Anura the upper hyoid element is subdivided as 
in a normal branchial arch: here the terms for the segments are “ inter-stapedial ” for 
the upper, and “ medio-stapedial ” for the lower, hyal piece. 
The lower band of the hyoid, which w r as coeval in development with the mandible, 
and antorbital in position, becomes, as a rule, confluent with the floor of the tympanum 
—a growth from the basal plate or “ parachordal.” 
It may articulate with that part as in the Common Frog, or be suspended by a 
longish ligament as in Dactylethra, or the bar may be partially absorbed (often on one 
side) as in Rana hexadactyla, or the middle part may become fibrous as in Rana 
tigrina, or the proximal and distal parts, as in Bufo agua, or the whole may vanish as 
* As pointed out to me by Mr. Howes. 
