214 MR. W. K. PARKER ON THE STRUCTURE AND 



continuous, above, with the ethmoid, and, behind, the dilated post-palatine is not 

 segmented from the pterygoid cartilage as it is in other species of this genus. 



Tlic whole of the cartilage of the palatine region is a large L-shaped band, it 

 narrows at its starting from the ethmoidal wing (e.pa.), dilates into the pre-palatine^ 

 and forms a rounded projection, beliind, where it passes into the pterygoid band 

 (py.)- The palatine bone {^kl, pa'.) is composed of two pieces, imperfectly soldered 

 together ; the main piece is the ectosteal plate, the normal Anurous bone, it is large 

 and falcate. The superficial bone is one-fourth the size of the other ; it is an irregular 

 rod, with a distinct suture in front, and lies somewhat obUquely on the middle of tlie 

 fore edge of the main bone. This is the true counterpart of the dentigerous palatine 

 " parostosis " of the Urodeles, and belongs to the same category as the vomers. Tlic 

 pterygoid bone (p5'.) is very large, falcate, and two-membered, behind ; contrary to ride 

 it overlaps the pre-palatine, above (fig. 1), where, abnormally, it is more developed 

 than below, and throws the remains of the unused cartilage on the ventral aspect, instead 

 of the dorsal. Also, unlike the other species, it has a large, Jree, Ranine pedicle, the 

 pterygoid only ossifying the surface of the thick stump of the original pedicle, and not 

 binding it down; hence the joint is free; it is an oblong condyle moving in a shallow 

 glenoid cavity. 



Below the confluent otic process, hidden by the squamosal (fig. 1, sq.), the outer 

 member of the suspensorium forms the partially retreated quadrate condyle ('/.(".) ; 

 this is very obhque, long, reniform, and has the quadrato-jugal a little confluent with 

 the cartilap-e of which it is the base. Between these short thick forks we liave the 

 large semi-oval Eustachian opening {eu.), the hinder boundary of which is formed by 

 the large confluent stylo-hyal (st.Ji.). 



The "annulus" (a.ti/.) is three-fourths the average size, and like that of B. vulgaris, 

 is widely open above, and not a perfect ring as in most of the species of this genus. 



The stapes (fig. 5, sf.) is large, thick, umbonate, and notched in front; the medio- 

 stapedial {m.st.) has an upper rounded, and a lower lip-shaped, cartilaginous process, 

 but no separate inter-stapedial. The shaft is twisted and carinate in front, and is 

 bent outwards to reach the outer edge of the suspensorium ; I do not see here, what 

 in old specimens of B. vulgaris can be plainly seen, namely, a partial segmentation of 

 the bone at this outward bend. The extra-stapedial {e.st.) is sub-peltate, and the 

 supra-stapedial band {s.st.) is perfect and confluent, above. 



The mandi))le (fig. 3) is normal, Init the articiilar bone {ar.) is feebly developed ; 

 the condyle {ar.c.) is long and reniform, and from it the rod {ink.) is scarcely lessened. 

 The dentaiy {d.) is three-fifths the length of the ramus, and the mento-Meckelian 

 {m.mh.) has only ossified half of the inferior labial. 



The cerato-hyal (fig. 4, c.hy.) is broad, and doubles its widtli in the lower half; there 

 is a small hyi^o-hyal lobe, and the notch of the basal plate (b./i.hi-.) is deep. The 

 plate itself is of good width and of great length ; the fore lobes are large and ear- 

 shaped, the liiiid lol>es ligulate and luicinate, hiwards. 



