582 SYSTEMATIC RELATIONS OF FISHES. 
paratus, we find an undivided ceratohyal, three branchihyal arches, 
and no inner and but two outer bones of the superior branchihyals, 
present in Polypterus. In Lepidosteus and Amia we have the 
double ceratohyal, four branchihyal arches, with four outer and 
four inner superior elements, characters of the typical Teleostei. 
The maxillary bone of Polypterus, instead of being free distally, 
as in fishes generally, is united with an ectopterygoid, and with — 
bones representing, in position at least, postorbital and malar. 
In the other genera the relations of the maxillary are as in osse- 
ous fishes. 
The sturgeons (Accipenseride) agree with Amia, etc., in all of _ 
these points but one, differing only in having the superior cerato- 
hyal and several of the superior branchihyals cartilaginous. The 
one point of distinction is the extension of the basal radial sup- 
ports of the ventral fin all across its basis as in Polypterus. The 
pectoral fin is, on the other hand, much as in Lepidosteus. Thus 
the sturgeons combine in this one respect, the features of both 
divisions. Both the basal ceratohyals are cartilaginous in this 
family; the superior only is cartilaginous in Polypterus, Lepi- 
dosteus and Amia, while both are ossified in the old Teleostei, 
except in the eels. In these the inferior is cartilaginous, while 
the superior is coossified to the ceratohyal. Thus in one unimpor- 
tant character Polypterus agrees with its former associates, but 
differs more from others of them—the sturgeons, than from the 
bony fishes. 
Another character of both Lepidosteus and Amia betokens a cer- 
tain relationship to Polypterus, viz., the complexity of the mandi- 
ble, especially in the possession of a coronoid bone. But here 
again Accipenser only possess an osseous dentary, while Gymnatr- — 
chus and Gymnotus have the angular and articular bones distinct 
from the dentary, wanting the coronoid and opercular. In mos 
bony fishes the angular is not distinct. 
It is thus evident that the sub-class Ganoidea cannot be main- 
tained. It cannot be even regarded as an order, since I will show 
that Lepidosteus, Accipenser, and Amia, are all representatives of 
distinct orders. I hope also to make it evident that Polypterus 
should be elevated to the rank of a sub-class or division of equ 
rank with the rest of the fishes, and with the Dipnoi already 
adopted. 
The question may be discussed as to whether naturalists av 
