580 EDWARD PHELPS ALLIS, JR. 
these latter fishes I have made no special search for these ecarti- 
lages, but it seems to me practically unquestionable that, as al- 
ready stated, they are represented in the suprapharyngobran- 
chials of van Wijhe’s (’82) descriptions of ganoids and Polyp- 
terus. These suprapharyngobranchials are shown by van Wijhe, 
sometimes as independent cartilages, sometimes fused with the 
infrapharyngobranchials, and sometimes fused with the epibran- 
chials of their respective arches. In Polyodon van Wijhe did 
not find any of them, but Bridge (79, p. 709) found, in each of 
the first two branchial arches of this fish, a little cartilage, de- 
' seribed by him as a short pointed cartilaginous ray, directed up- 
ward and backward from the upper posterior angle of the related 
epibranchial; these so-called rays thus certainly being strictly simi- 
lar to the cartilages described by van Wijhe as suprapharyngo- 
branchials in Acipenser. The relations of the suprapharyngo- 
branchials to the vena jugularis are not given either by van Wijhe 
or Bridge, but it would seem as if they must lie lateral to that 
vein. If so they are certainly extrabranchials, and it is evident 
that all the various forms of suprapharyngobranchials described by 
van Wijhe would arise by simple adaptations and fusions of such 
cartilages with one or the other of the inner cartilages of its arch, 
or with that cartilage together with the related interarcual. In 
Amia there are, furthermore, indications that certain of the ven- 
tral extrabranchials have been preserved, for in this fish there are 
ventro-mesial processes on the third and fourth hypobranchials, 
shown by both van Wijhe (1. c.) and myself (’97; fig. 50, pl. 33), 
which le ventro-mesial to the vena jugularis inferior and hence 
in the same protective relation to that vein that the bases of the 
ventral extrabranchials have in the Plagiostomi. <A similar pro- 
cess is also shown by van Wijhe on the third hypobranchial of 
Acipenser. The so-called suprapharyngobranchial of the first 
branchial arch of my descriptions (’03) of Scomber I now con- 
sider to be an interarcual and not a suprapharyngeal (extra- 
branchial) cartilage. 
The pharyngeal and hypal elements of the branchial arches of 
the Plagiostomi all project postero-mesially, instead of antero- 
mesially in the lines prolonged, respectively, of the epal and 
4 
