DEVELOPMENT OP THE SKULL IN THE BATRACHIA. 205 



steep maxillary (figs. 1 and 3, n.,m.r.), the bone swells out to finish the front of the orbit ; 

 these bones are blunt over the wide snout, which lies beyond them ; their antero- 

 extemal edge is straight. 



The palatine processes of the premaxlllary {fig. 2, jja.) grow well inwards near the 

 mid-line ; on the right side the outer angle forms a separate bone {p^'-). 



The nasal j^vocesses (fig. 3, px.) are thick " uprights," propping up the snout, and 

 padded with the first labial (u.l^.) ; together, these bones occupy a large part of the 

 fore face. 



The maxillaries (mx.) are high rough slabs ; their lower margin is gently concave, 

 and along it and along the dentary edge of the premaxillaries (fig. 3) there is a row of 

 sharp denticles growing from the epidermic sheath ; these atavistic memorials of teeth 

 might easily be mistaken for the organs they so closely imitate. The upper margin 

 of the maxillary is sinuous ; it rises four times, in front, under the nasal, where the 

 pterygoid joms it, and as it binds upon the quadrate -jugal. The palatme margin 

 (fig. 2, mx.) is well developed, and of equal breadth up to the fore edge of the cavity 

 for the temporal muscle ; the bone then lessens into a sharp curved style, which binds 

 the quadrato-jugal up to the hinge — nearly. The latter bone (qj-) is a flat style, and 

 is continuous with the bony half of the quacb-ate {<[.). In front, over the joining of 

 the premaxillary and maxillary, there is a semi-chcular septo-maxillary (fig. 3, s.m.r.) 

 obliquely set on to the latter, and raising it nearly to the height of the bone in front 

 {n.2)X.). Behind this part there is a fenestra between the nasal pouch (fig. 3) and the 

 concave edge of the maxillary. 



The squamosal (sq.) is quite Batrachian, but it is exorbitantly large ; it is a roughly 

 crucifonn bone, Mnth a sigmoid stem, and a large over-lying temporal plate, which is 

 lozenge-shaped (fig. 1). This oblique plate is thick in front, and unites by suture with 

 the postorbital projection of the roof bone (f.p).) ; the scooped part lies like a scale on 

 the parotic region. The postorbital process of this bone looks downwards, it is blimt 

 and short ; it only reaches half-way to the jugal crest ; the pre-opercidar portion' is 

 long, curved backwards, and carinate inside where it binds upon the quadi-ate. 



The parasphenoid (figs. 2, 3, i^a.s.) is only half as long as the basis cranii ; and is 

 very pecuhar. The fore part, for a fourth of its length, is a narrow style ; then the 

 bone widens at once, and is notched on both sides. The hind part is triangular, and 

 the side bars are oblong and widest behind, and articidate by a toothed sutiu'e to the 

 pterygoids {pg.). 



The vomers (fig. 2, v.) stand, beliind, against the huge palatines ; they are sub- 

 crescentic .shells of moderate size, and are separated by a space more than equal to their 

 own width. There is only a pye-w&x'iol snag ; on the left side this is a distinct bone 

 like the distinct palatine ossicle detached from the premaxdlary on the riyht .side {px'.). 



In corapaiing this type of skuU with the " norma," a good proportion of the dis- 

 crepances wUl be seen to be divergences, also, from the typical Bufonine .skidl, such as 

 that of B. vultjaris, or the larger skull of B. pantherinus. 



