Observations on Amphiuma. 321 
beneath it. Meckel’s cartilage runs forward nearly to the symphy 
sis. The hyoidean arch consists of a short hypohyal and a longer- 
ceratohyal. The latter has along its inner side a narrow and easily 
separable splint of bone. The branchial apparatus is much as in 
the adult. The first arch is partially ossified. No other ossifica- 
tions than those mentioned are found in the cartilaginous cranium. 
There are several membrane bones. A large parasphenoid under- 
lies the pituitary space and the basilar region. In front of this, in 
the roof of the mouth, are dentigerous vomers. The maxillaries 
are probably not represented by actual ossifications, but two rows of 
dental papills shows where they will appear. There is no palatine 
or pterygoid. The premaxillaries are present and completely con- 
solidated. Their nasal spine is long and they bear prominent teeth. 
The side walls of the skull are ‘protected by small frontals and 
larger parietals, but it is the frontal process alone of the parietal 
that is present. The suspensorium is partially covered by a 
squamosal, 
The Meckelian cartilage appears to be ensheathed, as in the adult, 
by only two bones. One of these is the dentigerous dentary, which 
almost meets its platetrope at the symphysis. The other, lying 
along the inner side of the mandible, extends from the posterior 
extremity of Meckel’s cartilage to a point two-thirds of the distance 
to the symphysis. It may be regarded as an angulo-splenial. It 
no teeth, as does the splenial frequently in the urodeles. 
The shoulder girdle consists of scapular, coracoidal and precora- 
coidal portions, with no ossifications. These elements lack much of 
meeting in the middle line of the body below. There are a hume- 
Tus, radius and ulna, carpals and phalanges. The humerus alone 
has a center of ossification. 
The anterior vertebrae, at least, are ossified, the neural arches 
having coalesced with the sheath of bone surrounding the notochord. 
The upper portion of the neural arch is not yet ossified. 
Only cursory observations have been made on the brain. Asa 
_ whole it is far less elongated than in the adult. This shortening is 
a Principally to the prosencephalic lobes, more than half of whose 
ength lies alongside of the di- and metencephalon. Laterally, the 
€pencephalic folds run so far forward as almost to touch the poste- 
nor extremity of the cerebral hemispheres. 
