234 Mr. W. K. PARKER ON THE STRUCTURE AND 



ralised) condition of ;i beaked snout is found in this genus Xenophrijs (Plate 23, figs. 

 5-7), among the toothed Anura. From the snout to the ethmoidal region the ossified 

 subnasal laminae (fig. 2, p.n., eth.) form a concave plate, in front of which the nerve 

 passages [n.n.) are seen wide apart, and outside of them, the small pro-rhinals grow 

 out, and are imbedded in the premaxillai-ies {p.i'.). The nasal roof (fig. \, p.n.) is 

 moderately convex ; the skull is very shallow at this part (fig. 3), which condition is 

 increased by the hollow form of the fore-palate. 



The subocular spaces are an almost perfect oval, and the bars surrounding them are 

 strong. The nostrils (e.n.) are wide apart, their valves {u.V-.u.V'.) are normal. The fore 

 skull is formed of the combined ethmo-nasal cartilages and bones, which are continuous 

 with the palatines. The pre- and post-palatine regions of the latter are adze-shaped ; 

 there is some cartilage left above, in this part (fig. 1, e.pa.), and also along the whole 

 palato-suspensorial bar, into the quadrate {q.c) and jDedicle ( jxZ.), which has a free joint 

 on the skull ; the quadrate is but little affected by the quadrato-jiigal. The forks of 

 the pterygoid bone [pg.), which enclose the small oblique Eustachian jDOUch {eu.), run 

 backward to the same transverse line, for the quadrate hinge is arrested in its retreat. 

 Its condyle {q.c) is long-reniform, and its front edge is opposite the exit of the optic 

 nerve (II.), an extremely forward position in an adult Anuran ; also the left is not in 

 symmetry with the right, and is not nearly so fiir back. 



Considering that the pedicles {pd.) once were continuous with the basis cranii 

 under the outgoing trigeminals (V.), their present position sjjeaks of a large amount of 

 metamorphosis, after all ; they are very wide apai't now, and far from the skull-base. 



In the obtuse angle formed by the suspensorium and its splmt (fig. 3, sq.) there 

 is a very small semi-lunar annulus {i(.tij.), and in its inner rim the fore part of 

 the columella (e.st.) fits. The stapes (figs. 1 and 5, at.) is an oblique half oval ; it is 

 convexo-concave, and umbonate. 



The columella has no proximal joint, but the medio-stapedlal (m.st.) is very thick, 

 above, and the most solid part is oblique, emarginate, and unossified ; it wedges itself 

 within the oblique jiail of the stapes. The shaft is bent on the clubbed end, and 

 ceasing to be bony, below, soon dilates into the broad trowel-shaped extra -stapedial 

 (e.st.), which has no ascending ray. 



The naiTow stylo-hyal (st.h.) is uniting with the tympanic fioor, and does not 

 enlarge in the cerato-hyal region (fig. 4, c.fii/.) until near to the hypo-hyal loop. 



The basal plate has three rounded notches in front ; the median space is deep and 

 narrow between the hypo-hyal bands ; there is, right and left, a small ear-shaped 

 front " lateral lobe." There is no hind lobe, and the basal plate is very long (narrow 

 beyond all precedent in this group, the " Anura "), and ends in two strong, upbent, 

 widely diverging thyro-hyals (t.hi/.). The mandible (fig. 4) is normal, the dentary (c^.) 

 is half as long as the ramus, the articular surface is large and obliquely renifomi ; the 

 articulare (ai:) has not ossified the rod {ink.) appreciably, and the mento-Meckelians 

 {m.mk.) are large. 



