56 
of my descriptions of Amia, but also the so-called primary part of 
the squamosal of Teleosts. The dorsal, dermal part of the squamosal 
of Teleosts has simply retained that primary independence from the 
underlying primary part of the ossification that is ascribed to it by 
Scumip-Monnarp, and has fused with the lateral edge of the parietal. 
It has also fused with, and wholly appropriated to itself, that fibrous 
component of the bone of Teleosts that forms, in those fishes, the 
posterior process of the bone, this process being described, in 
Polypterus, by TRAQUAIR, and more fully by POLLARD, as a posterior 
process of the squamoso-parietal. In old specimens this process, 
called by POLLARD the squamosal process, is said by him to become 
completely anchylosed with the so-called opisthotic (No. 26, p. 407), 
the primary and secondary parts of the squamosal thus finally acqui- 
ring, in Polypterus, the connection usually found in Teleosts, and 
the squamoso-parietal and opisthotic necessarily forming a single bone. 
Assuming that: I am correct in the assumptions made above, the 
general relations, in Amia, Scomber and Polypterus, of the several 
parts of the several bones here concerned, to each other and te 
associated structures, would closely resemble each other. Thus, in 
Polypterus, the so-called opisthotie is said by TRAQUAIR to be “drilled 
by both the external and posterior semicircular canals of the ear”. In 
Scomber these two canals traverse, respectively, the primary part of 
the squamosal and the exoccipitale; and in Amia the posterior canal 
“kommt fast in unmittelbare Beriihrung mit dem Exoccipitale” (No. 27, 
p. 206), the external canal lying in the cartilage of the side wall of 
the skull and having no direct relation whatever to the squamosal. 
In Polypterus the squamosal process of the squamoso-parietal is said 
by POLLArD to give attachment to one of the stoutest tendons of the 
neck muscles. In Amia and Scomber the corresponding process of 
the squamosal gives attachment to fascia connected with the muscles. 
of the trunk. In Polypterus the opisthotic, or cranio-spinal, process 
of PoLLARD’s descriptions is said by him to be connected by ligament 
with the posttemporal scale, and this ligament is said to become, in 
older animals, completely ossified. In Amia and Scomber the posterior 
process of the intercalar gives attachment, by ligament, to the so- 
called leg or pedicle of the suprascapular. In Polypterus the nervus 
glossopharyngeus is said by POLLARD (No. 26, p. 397) to give “off a 
fine branch which passes dorsally and vertically upward and penetrates 
the process of the Petrosum”. Then in a foot-note he adds: “It doubt- 
less supplies one of the mucous canal organs”. In his Fig. 13, Pl. 28, 
he shows this nerve piercing the posterior process of the so-called 
