DEVELOPMENT OP THE SKULL IN THE BATRACHIA. 201 



The vomei-s {r\) are vather small and edentulous, but are spiked both before and 

 behind the inner nostrils ; their inner lobe Ls ear-shaped. 



This average Toad's skull differs from an average Frog's skull in several particulars : 



1. It is shorter, deeper, stouter, and altogether rougher; the endocranium is more 

 solid, but scarcely more ossified, than in the Frog. 



2. The nasal region has the roof deficient, and the pro-rhinals pointed and turned 

 inwax'ds. 



3. The cartilaginous palatines are segmented, both from the ethmoidal wings, and 

 the pterygoid cartilages. 



4. The palatine bones are cultrate, and the pterygoids are veiy broad, and bind 

 down and fix the joint of the pedicle. 



5. Tlie quadi'ate is {lai-tly ossified. 



G. The columella has an imperfect supra- and no inter-stapedial. 



7. The roof bones meet the squamosals over the temples. 



8. None of the bones bear teeth. 



56. Bu/'o melanostictus. — Male, half-grown ; 2^ inches long (old specimens measure 

 5 inches). India. 



The skull of this young individual comes very near to that of an adult B. vnl<jaris, 

 and the skulls of old specimens almost rival the very large kind next to be described, 

 viz. : B. agua ; they are, however, very variable as to the degree in which the bony 

 ridges are developed, some having theu' skulls much more crested than others. 



This is a very short, broad skull (Plate 35, figs. 7, 8), its length is only three- 

 fourths of its breadth; the condyles of the quadrate (q.c.) I'each as far back as the 

 exit of the vagns nerve (X.). The occipital condyles {oc.c.) are large, infero-posterior, 

 and are separated by a narrow notch, which is the end of the basi-occipital synchon- 

 drosis. The prootics and ex-occipitals {pr.o., e.o.) are confluent, and the bone half 

 surrounds the optic fenestra (11.). The orbito-sphenoidal region {o.s.) is cartilaginous, 

 and occupies two-fifths of the orbital region. The auditory capsules are ossified as far 

 as to the outside of the horizontal canals ; but the tegmen {t.ty.) is cartilaginous, as 

 also is the floor of the vestibule {yh.). The girdle-bone (eth.) occupies its own 

 (ethmoidal) region very exactly; the nasal territory {n.r., s.n.) is quite free from true 

 bone. The form of the various parts is quite like what is seen in B. pantherinus. 

 The palatine bones {pa.) are sub-arcuate, and on the left side there are two sub-equal 

 bones. 



The pteiygoids {p(J.) Ijind down on the pedicle {pd.) ; the quadrate region is soft, 

 the aunulus {a.tij.) perfect, and the stylo-hytd {st.h.) confluent above. The stapes 

 (figs. 9, 10, 11, s<.) is oval and plano-convex ; there is a distinct reuifonn intei-stapedial 

 cartilage {i.st.) ; the medio -stapedial {m.st.) is a tloick bony rod above, and is very 

 narrow and decurved below. The cartilage proceeding from it has been almost 



MDCCCl.XXXI. 2 u 



