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MR. W. K. PARKER OK THE STRUCTURE AND 
the palato-suspensorial arch is rather feeble; the pre-palatine (fig. 4) is blunt; the 
pedicle (pd.) is short, and the quadrate region (fig. 3, q.o.) of the average length; it is 
partly ossified. The pedicle glides on a disk, which has a thick rim ; the part of the 
pterygoid (pg.) which invests it is at right angles with the main part. The palatine 
bone ( pa. ) is a feebly falciform lamina lying loose under the cartilage; the condyle for 
the jaw (q.c.) is large and reniform. 
The “annulus” (figs. 3 and 5, a.ty .) is one-third less than the average size, and is an 
oblique, open crescent; the stapes ( st .) is a very regular ellipse, of medium size and 
slightly calcified. In front of the stapes, and passing a little inside its antero-superior 
edge, there is another ovoidal cartilage (co.), from the outside of which there grows a 
thick, short spike, also unossified; this ends in a fibrous thread which passes over the 
hind limb of the annulus and under the facial nerve (VII.). This “columella” is an 
accurate counterpart of that of the young Toad (fig. 9); the inter-stapedial region is 
here, with a rudiment of the medio-stapedial. The stylo-hyal ( st.h .) is small above, 
and only partially confluent; the cerato-hyal band (fig. 6, c.hy.) is narrow and uni¬ 
form; the hypo-hyals have a lobe, growing forwards, and are straight and long, 
bounding the very deep, semi-elliptic notch. The basal plate is long and wide, the 
anterior and posterior lobes are part of the same expansion, and the front part has a 
larger outer and a smaller inner projection; the thyro-hyals ( t.liy.) are long, straight, 
and but little divergent. The Eustachian openings ( eu .) are of moderate size and 
circular. The investing bones are very much like those of the young Toad (figs. 7, 8); 
the fronto-parietals (f.p.) leave the superoccipital region bare, behind, and do not cover 
all the fontanelle, and but little of the girdle-bone in front. The nasals (n.) are wide 
apart, they do not overlap much of the nasal region, and cover but little of the 
roof; they are small sub-crescentic shells. The premaxillaries (px.) are well under the 
snout, and are tilted forwards, above; the maxillaries, quadrato-jugals, and squamosals 
(mx ., q.j., sq.) are normal, but feeble; I find no septo-maxillaries; the parasphenoid 
and vomers are like those of a young Toad. The mandible (fig. 3) is normal, but 
rather feeble ; the dentary ( d .) is more than half the length of the ramus. 
As compared with the “ norma,” this skull has the following modifications:— 
1. Its general shape is rather triangular than semi-elliptical; and its prenasal is 
very large and projects in front, like that of an “ Elasmobranch.” 
2. It has only one fontanelle. 
3. Its hind skull has only one ossification on each side. 
4. The whole nasal region is very generalised and Raiine. 
5. The annulus is small and very open. 
6. The columella is only a cartilaginous rudiment. 
7. The lateral lobes of the basal plate are confluent, and give off three spurs on each 
side. 
8. There are no dentigerous bones. 
9. The investing bones generally are very feeble and arrested. 
