DEVELOPMENT OF THE SKULL IN THE BATRACHIA. 245 



above (fig. 8), in the groove on the outer edge of the pterygoid. Also it forms a large 

 oval condyle which fits on a shallow facet on the front of the ear-capsule (tig. 9, pd.) 



The outer fork, or quadrate "pier," reaches but little further back (fig. 9), but is of 

 great length when seen from the side (fig. 10) ; its condyle (figs. 9 and 10, q.c.) are 

 large, convexo-concave, and reniforni. 



In descending, the quadrate pier is curved like a half-bent knee ; its splint, the 

 squamosal (sq.) fits to this bend ; the hinder (inner) lobe of the condyle is higher than 

 the other. The pedicle (pd.) grows inwards exactly half as far as it did in the Tadpole; 

 the fixed band, from the foramen ovale to the eidarged part which becomes the condyle, 

 has all been absorbed. 



The quadrate (fig. 9) above the condyle is only slightly ossified by the quadrato-jiigal. 

 The annulus (ci.tt/-) is an open crescent ; it is broad, and its front horn is higher 

 than the other ; its size is normal. The Eustachian [en.) tube is small — half the normal 

 size, and cu'cular; the cavity altogether is very limited. The stapes (figs. 8, 10, 12) 

 is very large, long-oval, with two anterior emarginations, and but little bossed. The 

 columella, altogether, is relatively as large as its morphological counterpart in the 

 Skate, viz.: the "hyomandibular." 



The inter-stapedial (fig. 12, i.st.) is a short sub-oval segment of cartilage; the 

 medio-stapedial {m.st.) is a long rod of bone, thick and clubbed, proximally ; the 

 supra-stapedial (s.st.) is a bud of cartilage growing from the upper edge of the short- 

 stalked, peltate extra-stapedial (e.st.). 



The mandible (fig. 10) is curved more than usual; its mento-Meckelian element 

 (m.mk.) is unusually large, showing that metamorphosis did not lessen the actual size 

 of the lower labials. 



The stylo-hyal (fig. 9, st.h.) is continuous with the small tract of unossified cartilage 

 at the outer part of the auditory region. The cerato-hyal (fig. 11, c.hi/.) is rather 

 broad, and turning back, as ahypo-hyal (li.hy.), without a lobe, it partly spUts into two 

 bands, a hyoid and " extra-hyal," as in some other kinds. • 



The notch of the basal plate is deep and the plate itself (h.h.hr.) rather shorter than 

 usual, and swollen. The fore lateral lobe is very large, and crenate in front ; the hind lobe 

 is normal, but outstanding. The thryo-hyals {t.hy.) are long and rather flat ; between 

 these roots there is a thick pentagonal wedge of bone — a " basi-branchial " {h.hr^.). 



The investing bones are similar, as to thickness and strength, to those of the 

 larger " Ranida3 " and " Polypedatidae " of the same region. 



The fronto-parietals (figs. 8, 10, f.p.) are very short and broad ; their interorbital 

 region forms, together, a square, with a small projection on each side, near the front ; 

 they are bevelled behind, as they pass into the expanded temporal region. Here, and 

 over the fore half of the hind skull, they are modelled most accurately on to the endo- 

 cranium, have rounded ends, and also are wrought into a rounded, low, transverse 

 crest on each side. 



In front these bones are scant where the ethmoidal wings grow out ; they touch the 



