170 PROF. W. K. PARKER ON THE MORPHOLOGY 



sphenoid lies between the trabecular sections, and the parietals are finishing the roof 

 over the hind brain. The sections of the arches are made through a more backward 

 part ; they differ but little from the last, yet the hyoid (c.hy) has been severed where 

 it is smaller, and the second basibranchial lies low in the throat ; the pterygoid bone is 

 running towards the quadrate (q). 



The fifth section (PL XIV. fig. G) is through the apex of the notochord (nc) ; the 

 anterior semicircular canal (a.sc) is severed near its junction with the posterior and the 

 horizontal canal (h.sc) through its middle. 



The roof of the ear-capsule is perfect, but the floor is imperfect ; for the fissure for the 

 fenestra ovalis is now gaping, and part of the jagged edge of cartilage is becoming 

 rounded into the stapes (see PI. XIV. fig. 2,fs.o). 



The superoccipital margin is imperfect here ; below, the imperfect cephalostyle (nc) is 

 seen to be united with the parasphenoid. 



The sixth section (Plate XV. fig. 3) was made behind the superoccipital roof, through 

 the posterior semicircular canal and the hind part of the horizontal (p.sc, h.sc). The 

 cartilage grows inwards round the latter, and mesiad of this inflection we see the cleft 

 which becomes the fenestra ovalis. This section is behind the occipital roof, and through 

 the middle of the cranial notochord and the most solid part of the basal plate. 



The seventh section (Plate XV. fig. 4) is near the back of the ear-capsule ; it is the front 

 face of a solid section that is figured, taken a little in front of the condyles for the atlas. 

 The ear-walls are seen to be thick, and the sides of the parachordals (iv) are solid as com- 

 pared with the conjugational plate on which the huge notochord lies. The razor has passed 

 through the glossopharyngeal and vagus nerves (9, 10) at their exit, the former of these 

 nerves being close to the membranous labyrinth, and burrowing the periotic cartilage. 



2nd Stage. — Ripe embryos of Salamandra maculosa, 1§ inch long. 

 (" Cryptobranch stage.") 



Like the young of the Surinam toad (Pipa), the young Salamanders at birth are ready 

 for terrestrial life ; they, however, have had branchice before their escape from the oviduct. 

 The young Pipes never develop gills, and are developed in quasi-uterine pouches. The 

 changes seen in the skull of this stage as compared with the last are very great ; they 

 probably only took ten or twelve days for their development : the chondrocranium, in 

 the earlier stage, was very perfect, ripe for metamorphosis into a true Salamandrian 

 bony skull. 



The basal region (PL XV. fig. 6) is large and oblong ; and if the suspensoria be 

 removed, the sensory organs, in front and behind, form nearly equal expansions. In 

 the earlier stage the hinder, or auditory, were very large compared with the front, or 

 olfactory masses. 



Prom the foramen magnum to near the front of the internasal plate the whole base is 

 floored by one huge lamina of bone, the parasphenoid (pa.s), and through it the nakedness 

 of the proper cranium can be seen. 



Prom the region between the internal nostrils (i.n) to that between the foramina 

 ovalia the whole floor is imperfect, so that there is scarcely a trace of cartilage 



