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



cerato-hyals (fig. 4, c.hy.) gi-adually enlarge and contract again before they turn back 

 into the non-lobate hypo-hyal bands. The anterior lateral lobes of the basal plate 

 (b.h.br). are but little freed from the main sheet of cartilage ; they end in a blunt point 

 far in front of the deep, narrow notch. Then the plate is very narrow, and gives off 

 two small hind lobes. The fhyro-hyals {t.hy.) are rather short, bent strongly upwards 

 to embrace the larynx, diverge at a right angle, and end in a blunt piece of cartilage. 



The investing bones are intermediate between those of B. agua and Olilophus (Plates 

 36-38) ; belonging to a species so much smaller than the former, tliey are far less solid ; 

 their surface is smooth, except at their free sub-cristate edges, which are serrate, but 

 not beaded and ornate as in Otihphus ; on the whole, this skull is like that of either 

 of the two kinds between which I have placed it, and Imks them together. 



The broad fronto-parietals are {/■2^-) more than double the width of the inner skuU, 

 they are separated by a fronto-sagittal suture, and by an interrupted transverse suture 

 from the nasals (n.); they are lobate behind, exposing the superoccipital region, and ai-ti- 

 culate largely with the dilated squamosals behind the orbits. A lozenge of the girdle- 

 bone {eth.) is seen between the nasals and frontals ; the former (n.) are large, triangular 

 shells with a broad facial plate (fig. 3) ; they are jagged and pointed in front, and 

 almost reach the end of the snout. As in the embryo of the Pig, the premaxUlaries 

 (figs. 2, 3, ^;x.) are quite under the snout, and tlie long nasal processes are tilted 

 forwards ; the palatine processes are small and sharp. The maxUlaries (mx.) are deep, 

 but their palatine edge is not extended far inwards ; they reach nearly to the hinge of 

 the jaw, and are overlapped by the small quadrato-jugal styles (qj.) which keep distinct 

 from the quadrate piers. The squamosals (sq.) are almost entirely like those of B. agua, 

 but they have sharper and more serrated edges, especially along the temporal region ; 

 the descending part is small, long, and sigmoid. In front (Plate 37, fig. 3, and Plate 36, 

 fig. 8), old generalised ichthyic characters break out; there is a large, shell-like septo- 

 maxillary [s.mx.), and behind this a thin, sub-crescentic " pre-orbital " {i:>.oh.) ; it is 

 perched upon the ascending inner lamina of the maxiUary [mx.). The parasphenoid 

 (fig. 2, j)a.s.) is more normal than in B. agua, but its fore part is broader; the pterygoid 

 does, however, overlap the basi-temporal wing, obliquely ; there is a transverse crest 

 between the two wings. The vomers (y.) are thin, toothless shells, semi-circular in 

 form, but with post- and ^)'e-narial spikes, and a lobulated fore part ; they throw the 

 inner nostrils (i.n.) very far apart; the outer {I'.n.) are wide apai't, but these are at 

 nearly twice their distance. 



This is a very instructive skull, looked at in its Bufonine aspects ; as compared with 

 the Anvirous " norma " it is very remarkable ; it differs as follows :■ — ■ 



1. In the triangular form of the skull ; its breadth above, the height of the face, and 

 the shallowness of the cranial cavity ; also in the tendency to a crested and sculptured 

 condition of the outer bones. 



2. In the intense ossification of the endocraniiun, blotting out all landmarks, except 

 the necessary foramina. 



