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



skull, measured from the snout to the occipital condyles, yet in front of the pre-palatine 

 we have the fore part of the maxillary and the whole of the pre-maxillaiy. 



All at once in this part we come across a number of bones that have no representa- 

 tives in the Batrachia, generally, yet some of them correspond to familiar bones in tlie 

 Teleostei. I shall name these latter in accordance with my description of the " Salmon's 

 Skull" (Phil. Trans., 1873, Plates 6-8). 



As compared with what is seen in the typical kind, the palato-quadrate arch is 

 scarcely more ossified, but it is relatively, as well as really, very much larger. Instead 

 of a single palatine bone running across under the right-angled eth mo-palatine carti- 

 lages, there are several separate pieces." 



On the left side (fig. 2, j)rt.) tlie large sub-falcate ridged palatine is single up to the 

 handle or inner end ; there, however, three at least small sesamoid centres are seen. 

 On the right side the handle is entire, but the blade is composed of two unequal 

 additional bones {pu.) ; these are reversed in the figure. 



The huge sigmoid pterygoid bone (pj.) is single from its fore end near the outer 

 part of the palatine to the end of the quadrate condyle {(l-c); but the thick remnant of 

 the dorsal end of the suspensorium — the "pedicle" — is invested with, and more or less 

 ossified by, a group of bones. Two of these, on each side, are the familiar " raeta- 

 pteiygoid" and " mesopterygoid " (Plate 8, figs. 2-4, mt.pg., ms.p>g.) of osseous Fishes. 



The metapterygoid (Plate 8, fig. 2, mt.pg.) ossifies most of the pedicle (fig. 1, pd.), 

 leaving the thick ovoidal condyle soft ; but where it is passing inwards, at a right 

 angle to the pterygoid bone, there in front of its outer end is a bone one-third its 

 size : this is the mesopterygoid (ins.pg.). 



The large out-turned, almost vertical quadrate region is largely fenestrate (Plate 8, 

 figs. 1-4, and Plate 9, figs. 12-14) ; this fenestra is bounded above by a bridge of 

 cartilage, which passes to the " otic process " (cut through in these larger figures of 

 the details). 



That bridge is largely ossified by an additional centre {pd'.) or supernumerary 

 "metapterygoid." The fenestra is mostly occupied by three long splints — "inter- 

 suspensorial " membrane bones ; one is sub-falcate and twice as long as the others ; 

 their form is sub-oval (Plate 9, figs. 12-14, i.sp.). The hinder part of the proper 

 pterygoid is itself fenestrate on its inner face (Plate 9, fig. 13, pgr., sp.). 



On the outside this arch is well invested by the three normal subcutaneous bones, 

 viz. ; the squamosal, quadrato-jugal, and maxillary. The first of these (sq.) is remark- 

 able for the forwardly-bowed form and oblique position of its stem (Plate 8, figs. 1 



* This specimen, the gift of Dr. Mueie, came to me in a perfectly uninjured state; it had not been 

 caught (and possibly bruised) in capture, but it had lived in the gardens of the Zoological Society for 

 some time before it died. I often find specimens of Batrachia with some of these bones fractured in 

 capture, but I have learned how to distinguish them from suparnumerary bony centres formed naturally 

 in the animal. There are several kinds that show additional bones, but none at all comparable to this 

 species. 



