OF THE SKULL IN THE AMPHIBIA UKODELA. 175 



outwards and backwards ; the thick, oval, closely-fitting stapes (st) remains cartilaginous, 

 and is only attached to the suspensorium by a ligament *. 



The suspensoriuin has changed greatly since the time of birth ; in direction it has 

 moved its condyle from being opposite to the middle of the skull to an imaginary line 

 drawn across at the end of the paraspbenoid : this is equal to its average position in 

 adult Batrachia. It is foot-shaped below, the base looking outwards and backwards ; 

 all but the articular face is ossified (q) up to the middle of the otic process ; also the part to 

 which it adheres, and with which it becomes confluent, is soft. The ascending process 

 (pel) is small and terete ; it remains confluent with the alisphenoidal region. This 

 pedicle has a bulbous enlargement, like that which bears the condyle of the pedicle 

 in a Frog. 



But little of this expansion, which articulates with the ear-mass, is seen from below 

 (fig. 2), for it is ensheathed by the pterygoid {pg). This bone is hammer-shaped, and its 

 long head binds on the pedicle within and on the inside of the quadrate by its outer 

 lobe. The handle has used up the cartilage that grew from the suspensorium (PI. XV. 

 fig. 5) ; it is grooved where the cartilage lay (figs. 1, 3, 4), and its bluntly pointed end 

 has turned outwards to be tied by ligament to the zygomatic process of the maxillary 

 (mx). 



On the other hand, the bone from which it was segmented, the palatine (fig. 2, pa), 

 has grown further inwards, and reaches further backwards than the foramen ovale (5). 

 It has coalesced with the dentigerous region of the vomer (v), and the two tooth- 

 bearing tracts are rib-like bars of bone, whose arrangement under the parasphenoid is 

 lyriform. To one fresh from mere mammalian morphology, these sigmoid rods, and the 

 edentulous plates growing like wings from them in front, would be an inexplicable 

 puzzle. 



The anterior expansions are a new development of bone from the simple larval 

 vomers, and are a caducibrancliiate character. They are very elegant ; between these 

 wings there is a large semielliptical notch revealing the internasal cartilage and 

 rostrum ; their margin at this point is curled upwards. Their outer margin is lessened by 

 a large rounded notch, which bounds the internal nostril (i.n) ; behind this there is a lobe 

 which does not extend so far outwards as the fore part. They unite by " harmony " for a 

 short distance between the dentigerous bars ; the internal nostril has its rim finished, 

 outside by the maxillary (mx), and behind by the ethmopalatine cartilage (e.pa). 



The maxillaries have much, and the premaxillaries some, palatine expansion (fig. 2, 

 px, mx) ; altogether this is a very hard and finished palate for so low a type. The 

 palatine process of the premaxillary is short (fig. 2) ; its nasal process (n.p.i) is long and 

 inbent towards its fellow at the middle ; the frontals run under these bars, and in front 

 of the frontals the internasal cartilage is seen. The maxillaries (figs. 1 & 3, mx) have a 

 large and swollen facial plate ; and behind the nasal region these bones run back 



* Mr. A. Doran lias shown me a stapes, said to belong to this species, which is ossified and has a stalk. I find 

 nothing of the kind in tho specimens dissected by me ; and I think it probable that that specimen (in the Hunterian 

 Museum) belonged to another kind. Hereafter I shall have to describe this sort of stapes in Spelerpes and 

 Desmo'jnatlms ; it exists also in the Menopome. 



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