OP THE SKULL IN THE AMPHIBIA UEODELA. 183 



There is another facial bone in this species, the small, graniform, septo-rnaxillary 

 (fig. 7, s.mx). 



The forked, narrow, fore end of the parasphenoid (fig. G, pa.s) is largely invested by 

 the palato-vomerine plates ; further back it gradually expands to the basitemporal angle, 

 which is short and rounded. Behind this, as the bone narrows backwards, there is 

 another like projection, and at the middle the bone ends in a rounded manner. This 

 bone is subcarinate between the palatines ; the keel is grooved along its middle ; and 

 in the interauditory region the crest swells into a gentle convexity. 



Thus we see that even the huge parasphenoid becomes specialized, and even ornate, 

 in the higher Caducibranchs. 



The mandible is arched from chin to angle, both outwards and upwards (figs. 7 & 8) ; 

 the two bars form a strong and strongly bent bow. The articular part is highest, and this 

 height culminates in a sort of coronoid process, formed on the outside by the dentary (d), 

 and on the inside by the articular (ar). The splenial (fig. 4, sp) is a delicate style, most 

 pointed in front. There is but little cartilage left, and this is mainly articular ; the 

 condyle is placed obliquely, it looks upwards and backwards. 



The hyobranchial apparatus (fig. 9) has undergone similar changes to that of the 

 Salamander (Plate XIV. fig. 7) ; but there are some remarkable differences. 



The ccratohyal (c.luj) has become rounded and ossified in its upper half; its lower half 

 is very fiat and is soft. The hypohyal (Jt.hy) has become loosened from the main piece, 

 and now articulates directly with the soft fore end of the first basibranchial. 



Like the ceratohyal, the 1st branchial retains its relative size. The two pieces are 

 soldered together, and yet each has its own bony shaft (e.br 1 , c.bv 1 ). There is a little 

 cartilage at the free end of each segment ; and that of the ceratobranchial articulates with 

 the soft hind part of the 1st basibranchial. A delicate arcuate rod of cartilage articu- 

 lates with the same tract, but behind it. This is bowed inwards as much as the ossified 

 bar is bowed outwards ; it is the second cerato-branchial (c.br) whose upper piece has 

 been absorbed. This rod is fused with the synchrondrosial cartilage of the one in 

 front of it. 



The two other arches have been absorbed ; and so also has the 2nd basibranchial, all 

 but the lobes at its distal end (figs. 1 & 9, b.br). These are now thick semioval thyro- 

 hyals. Behind these nuclei, which bound the glottis (gl), there are two more patches of 

 cartilage (Lv) ; they are roughly-perforate irregular rudiments of the arytenoid cartilages. 



All but the ends of the 1st basibranchial (b.br 1 ) is occupied by a shaft-bone, so 

 that there are seven of these rods in these metamorphosed arches. 



Both the Anura and the Urodela curiously foreshadow the hyoid and thyro-hyals of 

 the higher types ; but the Frog casts its shadow towards the Mammal, and the Newt 

 towards the Bird. 



Species 3. — The Skull of Cynops pyrogaster (adult). 

 This Japanese Newt is larger and stouter than the last type ; its skull is very massive, 

 and greatly resembles that of Notoplithahnus, but is still more dense and strong. This 



25* 



