•JC)0 MR. W. K. PARKER OX THE STRUCTURE AND 



ethmo-palatine becomes segmented from the ethmoid, in front, and from the pterygoid 

 cartilage, behind ; in B. vuhjaris, also, the pedicle does not lose its apex. 



In Bufo ornatus and in Otilophus maryaritifer, as also in a Rappia from Lagos, and 

 in Diplopelma herdmorei, 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 Davtijhthra, Felodi/tes, and Bonhinatoi' there is 

 no jDalatine 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 mesopteiygoid 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 "Phaneroglossa." 



The zippei- hyoid element or columella is absent in Pseudophryne Bihronii, Phri/nisctis 

 Icevis, Phnjniscus varius, and Bumhinator igneus ; there is a small bony rudiment in 

 Pelohates fuscus, and a small unossified rudiment in Rhinoderma Darwinii. 



I find no trace of an annulus tympanicus m Pelohates, Bombinatoi; nor in two out of 

 three of the species of Phryniscus, viz.: P. heuis and P. varius; it exists without a 

 columella in Pseudophryne Bihronii, and with a rudiment in Rhinoderma. 



In several high kinds, viz. : Rana halecina, R. palustris, Phyllomedusa hicolor, &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 Chimoira, where there is a well- 

 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 pharyngo-brancliials themselves are in two 

 segments.'"' 



I find that in about half of the Anura the upi)er 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 low^er band of the hyoid, which was coeval in development with the mandible, 

 and antorhital 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 jDart may become fibrous as in Rana 

 tigrina, or the proximal and distal pai'ts, as in Bufo agua, or the whole may vanish as 



* As jioiiitftl out to mc l\v Mr. llowts. 



