116 
MR. W. K. PARKER ON THE STRUCTURE AND 
The annulus ( a.ty .) is of the typical size, broad, and its horns are not united. The 
stapes (figs. 2 and 4, st.) is large and oval, with its fore and upper edge but little 
bevelled. The medio-stapedial ( m.st.) is a strong and somewhat sigmoid rod, with 
but little cartilage at its proximal end, where it wedges in—without any inter- 
stapedial segment—between the stapes and the vestibule. 
Beyond the bone the cartilage soon expands suddenly into a sub-peltate extra- 
stapedial, with a ligulate supra-stapedial confluent above (e.st., s.st.). 
The mandible (fig. 3) is normal, but very long and slender. 
The stylo-hyal end of the hyoid (fig. 2, st.h.) is sub-acute, and loosely attached to the 
vestibular floor; it does not bind strongly round the hind margin of the Eustachian 
opening. Two-fifths of the band (fig. 3, c.hy.) at its lower end is reduced to a mere 
fibrous tract, and the hypo-hyals ( h.hy .) are quite loosed from their proper stem 
and are confluent with the basal plate (fig. 3, b.h.br.), into which they run by a 
ligulate stalk. This distal part is a very large ear-shaped emarginate leaf of cartilage, 
which, by its oblique, external angle overlaps the front lobe of the basal plate, a some¬ 
what smaller, more regular leafy growth, which runs almost transversely into the 
base by a shorter stalk. Behind this, on each side, there is the normal finger-shaped 
hinder lobe, a much smaller outgrowth of cartilage. At its root the fore end of the 
phalangiform thyro-hyal bone ( t.hy .) is set into the cartilage; this is terminated by 
an unossified lobe ; and the right thyro-hyal is considerably larger than the left. To 
the lower face of the proximal part of the right bone there is a curious splint applied: 
it is V-shaped, with all its points sharp ; the short stem behind, and the forks, which 
are crooked, run, the right forwards and outwards, and the left obliquely outwards in 
the other direction, under the root of the left thyro-hyal. 
This, which exists as a splint, I take to be an abortive attempt to produce an 
ectosteal basi-branchial bone; it will soon be described again in Alytes, and I shall 
have to refer to it when describing a more normal (“ endosteal ”) basi-branchial in 
Bombinator, Diplopelma , Callula, Engystoma, Rappia, and Pelodrycis 
The fronto-parietals ( f.p.) are similar to what we find in many sub-typical Anura, 
they are wedge-shaped shells of bone, with sharp fore and dilated hind ends. By 
these bones the great oblong fontanelle is reduced to an hourglass-shaped space, only 
half as large. The rest of the investing bones are normal; the nasals come within a 
moderate distance of each other, and are not very broad. With the upper labials— 
which are normal—there is, I believe, a small seed-shaped septo-maxillary. The pre- 
maxillaries ( px. ) are widely transverse; the maxillaries (mx.) thin and shell-like 
in front, and sharply styloid behind; and the styloid quadrato-jugal (q.j. ) is not 
evidently grafted on to the quadrate. 
The squamosals (sq.) are slight but normal; they fail to cover the short unossified 
“ tegmen tympani ” ( t.ty.). The parasphenoid (fig. 2 , pa.s.) is normal, and large in 
* This is one among many instances in which the metamorjjhosis to which these iclithyic types have 
been subjected has only partially obliterated the form and structure of the Fish. 
