204 UR. W. K. PARKER ON THE STRUCTURE AND 



is a very massive and wide l)ar, it is sigmoid, bending backwards towards tlie oval 

 Eustachian tube (eu.), and then growing directly inwards to articulate with the basi- 

 temporal l)ar of the parasphenoid (jxi.s.), whose end is, contrary to rule, most extended 

 at the hinder angle. These binding bars hide all but the hinder half of the vestibular 

 floors below ; they are sub-parallel with the palatine bars. 



The condyle of the quadrate (q-c) is a trochlea, grooved obliquely; the bar above it 

 is lai'gely ossified (fig. 3, q.) ; its height, from the otic process, which is covered by the 

 squamosal (sq.), is very great for a Batrachian ; this Toad has almost the deepest face 

 of any of its Order. 



The mandible (fig. 3) is normal ; none of its processes are large, but it is of con- 

 siderable tliickness, and only moderately ossified ; the rod {mk.) is contmued forwards 

 undiminished from the reniform condyle which lies in the grooved articidare (ar.). 

 The mento-Meckelian rod {m.mk.) is rather large, and the dentary (c^.) is three-fifths 

 the length of the entire ramus. 



The "annulus" (fig. 4, a.ti/.) is only of a medium size, and narrow ; but it is com- 

 plete. The stapes (figs. 4, G, 6^) is lozenge shaped, and has a boss for muscular 

 attachment ; it is followed by an equally large segment, the distal half of which is 

 ossified ; this is the inter-stapedial (i.st.). The next segment is the medio-stapedial 

 bone {m.st.) ; it fits obliquely under the first, is slightly arcuate and slender, and ends 

 in a thick sjsatulate cartilage, the extra-stapedial (cat.), which sends upwards a supra- 

 stapedial band (s.st.), that is confluent above. 



Botli the stylo- and hypo-hyal regions are absorbed, (figs. 2 and 5) and the cerato- 

 hyal (fig. 5, c.hy.) is a sigmoid band, sharp at both ends. 



The front notch of the basal plate {b.h.hr.) is deep and the plate itself rather nari'ow, 

 wath an angular projection on each side, behind; the thyro-hyals (tJuj.) are large, 

 bent, and divergent. 



The edges of the basal plate are thickened, and run in front into sharp liorns ; the 

 " anterior lateral lobes " are large, distinct cartilages, narrow in front, and dilated 

 behind ; the hind lobes are absent. 



The roof is almost as complete as in Calyptocephalus (Plate 21), but it is formed of 

 thick rough slabs, the lai-ge fronto-parietals, which are thrice the breadth of the top of 

 the endocranium. 



Their edges, like the edges of all the surface-bones, are very thick ; they reach 

 withm a short distance of the foramen magnum, and send out on each side a square 

 postorbital process to articidate with the corresponding squamosal {sq.). 



The whole dorsal region of the skidl is a shallow trough, through the raising of the 

 edges ; this is divided by the sutural line along the middle, which is complete from end 

 to end. More than a third of this sutiu-e is nasal, the rest fronto-sagittal ; the fronto- 

 parietals project furthest at the middle, and the nasals form almost half the orbital ruxi. 



Theu- pre-orbital process (figs. 2, 3, n.) is inmiense, and an ingrowth there would make 

 them correspond to those of the Tortoise. Besides forming a wide foot to rest upon the 



