No. 3.] MUSCLES AND NERVES IN AMIA CALVA. 663 
the ganoids described by van Wijhe, with or to the parasphe- 
noid and not with the cranium proper; where it is by the 
posterior element, it is directly with or to the cartilage of the 
cranium. 
The second arch also may be attached to the cranium by 
ligament or by tissue, but it is always less firmly and less closely 
attached than the first arch. In ganoids this attachment of the 
second arch is always to the parasphenoid and always by means 
of the anterior pharyngeal element of the arch, the posterior 
pharyngeal element, where it exists (and where it does not exist, 
the corresponding process of the epibranchial), being as a rule 
attached to the anterior pharyngeal element of the next 
following arch. 
The posterior arches do not reach the cranium. They are 
simply suspended in the tissues beneath it or beneath the front 
end of the spinal column. 
In Amia the suprapharyngobranchial, on the arches where 
it is found, lies behind the efferent artery of its arch rather 
than above that artery, as van Wijhe states, although it would 
certainly lie above the artery if prolonged. It lies also behind, 
and hence, in the same limiting sense, above the posttrematic 
branch of the nerve of its arch, and behind, or more properly 
external to, the external levator muscle of its arch, which mus- 
cle is innervated by a branch of the posttrematic nerve given 
off as that nerve passes outward in front of it. The supra- 
pharyngobranchial and levator muscle of each arch both lie in 
front of the pretrematic branch of the nerve of the next follow- 
ing arch. 
If now, in Amia, the relations to the muscles, nerves, and 
artery of the hyoid arch of that part of the hyomandibular 
that lies posterior to the facial canal be considered, it is 
seen: Ist, that it lies behind an artery which accompanies the 
truncus hyoideo-mandibularis facialis, which truncus contains 
the posttrematic elements of the nervus facialis; 2d, that it 
lies external to the adductor hyomandibularis ; and 3d, that that 
muscle lies behind the posttrematic branch of the facial nerve, 
between that branch and the pretrematic nerve of the next 
following arch, and that it is innervated by a branch of the post- 
