Note on the So-called Second Branchial Arch in Lizards. 
93 
Scincidae. — Mabuia trivittata has distinct epibranchials. At the lower 
end of each bar is a short, forwardly-projecting" process. According to 
Beddard, in the genus Tiliqua a ligament passes from this projecting process 
and is attached to the end of the hyoid cornu. The hyoid is separated from 
the ear. 
Lacertidae. — In Nucras delalandi the whole hyoid apparatus is very much 
like that of M. trivittafa. The ligamental strand between the lower portion 
of the epibranchial and the distal end of the hyoid is distinct. 
Zoyiuridae. — In Zonurus giganteus, Z. cordylus and Pseudocordylus micro- 
lepidotus the epibranchials are present. The hyoid has no relation with the 
ear. 
Hyobranchial apparatus of lizards. 1. Homopholis wahlhergi (fam. G-eckonidae), 
2. Same in ventral view. 3. Mahuia trivittata (fam. Scincidae). 4. Nucras 
delalandi (fam. Lacertidae). 5. Gerrhosaurus validus (fam. Grerrhosauridae). 
h. Hyoid arch. b. First branchial arch. e. Epibranchial. 
Gechonidae. — In Homopholis wahlhergi and Pa,chydactylus hihroni the 
epibranchial is present as a very slender thread of cartilage. The hyoid is 
intimately connected with the ear, passing along the posterior side of the 
tympanic membrane, which alone separates it from the columella. The 
hyoid and columella terminate very close together on the surface of the skull. 
Although as yet comparatively few genera have been examined, it seems 
very likely that the epibranchials are normally present in the following 
families of lizards: Oeckonidae, Lacertidae, Zonuridae, Scincidae, (rerrhosau- 
ridae and Anguidae ; and are absent from Agamidae, Varanidae, Heloderma- 
tidae and Iguanidae. Its homology can only be worked out embryologically. 
In the meantime, the ligamental connection between the lower portion of the 
epibranchial and the upper end of the hyoid cornu in certain families can be 
noted but not explained. 
