204 PEOF. W. K. PAEKEE ON THE MOEPHOLOGY 



wards, more outwards than in the last ; and although somewhat smaller, it comes near 

 to the larger maxillary spur {ma:). This pterygoid hlade has a base of cartilage, which 

 runs inwards to the alisphenoid region, and outwards into the fore part of the otic pro- 

 cess ; but behind, the quadrate (PI. XXI. fig. 7 and PI. XVIII. 9, q, ot.p) is seen as a 

 very solid wedge of bone, jammed closely in between the prootic and squamosal {pro, sq), 

 and flanked on its inner edge with the small pterygoid bone (pg). The condyle, carrying 

 a very solid mandibular ramus (figs. 7, 8, 9), is large, and has a deep and elegant troch- 

 lear cavity. 



The pterygoid bone (pg) is still smaller than in the last ; it is a small ear-shaped plate 

 lying in the axil of the suspensorium, binding it on its inner face, and the prootic on its 

 anteroinferior aspect, just in front of the escaping facial nerve (7). 



The other part of the palato-ptcrygoid bone {pa) is twice as large as the pterygoid ; 

 each plate is a small irregular hatchet, with a pointed blade that looks backwards ; the 

 back of the two blades are apposed, and each handle runs outwards and a little for- 

 wards, nearly completing the rim of the inner nostril (in), and partly underlying the 

 corresponding endoskeletal part, or ethmo-palatine (e.pa). The thickest part is where 

 the blade and handle join ; and there the bone is overlain by the vomer (v). These 

 bones, now, as well as the vomers, have lost their teeth, most probably, in this case, 

 through age. The whole plate is bound to its fellow by suture behind, and by simple 

 harmony in front ; and this structure is very remarkable in appearance, both the large 

 vomerine and the lesser palatine wings being separated by the pyriform internal 

 nostrils (i.n). The bones at the middle of the vomer, in one part of the suture, are 

 deficient, and leave an oblong membranous space beneath the septum nasi. 



The palatine plates of the vomers are less than in the last kind, and those of the 

 jaws are larger (fig. 7, v, px, mx) ; that of the premaxillary can be well seen in front of 

 the vomers. 



That bone is of less extent at its dentary margin than in Spelerpes, but its palatine 

 plate is more perfect, and the opening of the middle nasal cavity (m.n.p) is longer, both 

 above (fig. 6) and below (fig. 7). 



The upper surface of the premaxillary (fig. 6, px) is smooth and even ; for although 

 the cavity in it is large and well defined, yet it is not wrought into a rimmed funnel, as 

 in Spelerpes ; yet the bone is sulcate behind the upper opening. 



In front, on each side, the branches of the orbito-nasal nerve escape in the sloping 

 fore part of the bone at its solid part ; then a bony lamina is continued backwards, 

 enclosing the canal, and then widening, to end in two triangular processes that bind on 

 the fore part of the frontals (fig. 6, n.px,f). At its narrow part the premaxillary is 

 overlapped by the nasals («). These are very irregular triangles, with a concave base 

 looking forwards, and partly enclosing the cartilaginous narial rim (e.n) ; their outer 

 side lies on the maxillary (mx), and their apex on the corresponding frontals. 



Contrary to wont, the ectethmoid (e.eth) is not seen outside the orbit ; whereas in 

 Spelerpes it has an unusually large external plate. In Desmognathus this is partly due 

 to the lesser size of the bone, partly also to the larger and more perfect facial plate of 



