320 Observations on Amphiuma. 
As might be expected of the young Amphiume, hatched in a 
situation removed for some distance from the water in which it 
is to pass the greater part of its life, and to which it must with 
some difficulty find its way, its whole organization is in a far more 
advanced stage of development than is that of those Amphibia which 
are excluded directly into their yielding native element. A com- 
parison of the skull of the young Amphiume with that of the lar- 
val axolotl, as described by Messrs. Parker and Bettany, shows 
that the former corresponds in many respects to the earlier phases of 
the fifth stage of the latter. The axolotl in this stage is 1} inch 
in length, but when hatched was only about one-third of an inch 
long (Morphology of the Skull, p. 107). 
One of the most interesting features of the skull is the deficiency 
of cartilage in some regions. The otic capsule is well developed 
and large. Enclosed within it are the semicircular canals and a 
large otolith. The notochord runs well forward and is partially en- 
sheathed with bone. The exoccipitals, also, are ossified down almost 
to the notochord, and the ossification extends into the condyles. On 
each side there is a narrow band of cartilage that rises up from the 
hinder end of the ear-capsule toward the middle line, but it lacks 
considerably of meeting its fellow. Nowhere does the cartilage 
extend to the middle line above the brain, and nowhere is the brain- 
cavity roofed over with bone. In the basilar region there is on each 
side of the notochord a large elliptical fenestra in the cartilage, 50 
that there is only a narrow band lying along each side of the noto- 
chord, and a very narrow strip attached to each otic capsule. The 
trabeculee are united around the extremity of the notochord, and 
send back on each side a process to the otic cartilages. These tra- 
beculæ enclose a very large oval pituitary space. They are narrow 
and, meeting in front in the ethnoidal region, coalesce for a very 
short distance. ‘There are very short decurved cornua and narrow 
bands that run outward beneath the nasal sacs. From each trabe- 
cula there is given off on the outside a band of cartilage that runs 
forward and outward, and near its termination sends outward a 
narrow strip of cartilage over the posterior end of the nasal sacs. 
This process I regard as the antorbital. There is what appears to 
be a small postpalatine and a small pterygoid cartilage that does 
not extend back to the suspensorium. The latter is broad and 18 
directed forward. There is a stapes with the facial nerve passmg 
