DEVELOPMENT OF THE SKULL IN THE BATRACHIA. 
61 
fig. 8 . p.rh.) are well developed, but there is a small prenasal rostrum; the bulbous end 
of septum nasi is somewhat emarginate. The fore part of the palato-suspensorial car¬ 
tilage is thick, and forms a triangular pre-palatine ; its narrow ethmo-palatine pedicle 
has on its postero-inferior surface a slight palatine ossification (pci.). This cartilage 
in its pterygoid, quadrate, and auditory regions, is slender; the pterygoid bone (pg.) is, 
however, well-developed—not like that of a young Frog —and only leaves the upper 
and outer surface of the cartilage naked (fig. 7). Each pedicle (pci.) is small, and 
they are wide apart; so also is the quadrate region, but it ends in a large condyle 
(q.c.) that reaches as far backwards as to the middle of the stapes; this is quite an 
average retreat backwards. The Eustachian openings (eu.) are of medium size, oval, 
and transverse, and the space of the middle ear is well developed. 
The annulus (a.ty.) is large, and its horns nearly meet; the stapes (fig. 11, st.) is 
large and oval, with a moderate anterior scooping for the columella. 
This rod is well ossified in its main part, and has no appearance of belonging to a 
young individual; its interstapedial segment (i.st.) is small, pisiform, and lies between 
the large unossified lobes of the long, arcuate medio-stapedial (m.st., m.st'.). The extra- 
stapedial (e.st.) is a small, long-oval lobe of cartilage, and has no supra-stapedial process. 
The mandible (fig. 9) is quite normal. The styloid end of the hyoid bar (st.h.) is 
articulated with the ear-capsule; the bar itself (fig. 10, c.hy.) is narrow, and has no 
hypo-hyal lobe ; the two side lobes of the basal plate (b.h.br.) are small ; the thyro- 
byals (t.hy.) are normal. 
The narial valves (fig. 12, uF.uF.) are well developed and perfectly normal. 
The investing bones lend no support to the opinion that this is anything but a 
mature individual : they are well developed; those on the upper surface differ from 
their counterparts in a full-grown Common Frog, by the nasals (n.) being relatively 
much larger and nearer together, and the fronto-parietals (fp.) completely anchylosed 
along the middle—all save their pointed front ends, where a little of the fontanelle 
(fo.) is exposed. This common sheet of bone well covers the roof behind, and 
although the bone is thin, it is highly developed as bone tissue. 
The nasals (n.) touch the septum nasi (s.n.) and curving elegantly outwards in 
front, overlie the large sub-tubular external nostrils (e.n.) which are very wide apart. 
The fore part of the endocranium is well wrapped in the nasals, the pre-maxillaries 
(px.) and the maxillaries (mx.) ; these outer bones are but little developed in the 
palatine region, but are large and foliaceous on the outside. 
The jugal part of the maxillary is joined to a quadrato-jugal (q.j.) which is well 
grafted on to the quadrate : a good sign of maturity. 
The upper part of the squamosal ( sq.) is narrow, but all its regions are well 
developed. 
The parasphenoid (fig. 8 , pa.s.) is well developed and large, but is not so elegant as 
in the Common Frog, its angles behind being attenuated and not outspread ; the 
vomers (v.) are small crescents, widest in front and forming a mere hook behind ; 
