MAXILLARY AND VOMER BONES OF POLYPTERUS 379 
contains the hyomandibula, gives articulation, externally, to the 
hind edge of the preoperculum. The palatosuspensorium is 
said to be immovably fixed to the maxillary along the anterior 
two-thirds of its outer margin, and at what appears to be the 
hind end of this region of attachment—that is, at the posterior 
third of the length of the palatosuspensorium—there is a laterally 
directed process on its lateral edge which somewhat resembles 
the process on the lateral edge of the ectopterygoid of Polyp- 
terus; this process coinciding, in the latter fish, with the hind 
end of the tooth-bearing component of the maxillary. In two 
of Traquair’s figures the maxillary of Tristichopterus is shown 
ending at this process, and hence having a much less extensive 
posterior prolongation than that shown in the restored figure. 
The maxillary of Tristichopterus was thus probably more or 
less firmly attached both to the suborbital bones and the pre- 
operculum, and firmly attached to the outer margin of the 
palatoquadrate. It was therefore certainly incapable of inde- 
pendent movement. In this it agreed with the maxillary of 
both Conger and Polyodon, and if the bone were tuberculated 
it would seem as if it must be the homologue of the bone of one 
of these two fishes, and probably of that of Polyodon. 
In the suborder Actinistia there is but one family known, that 
of the Coelacanthidae, and there has been marked disagreement 
as to the homologies of the bones related to the upper jaw of 
these fishes. 
Macropoma mantelli, one of this family, was described by 
Huxley in 1866. The prodtic is said by him to be “a large 
plate of bone, rising perpendicularly towards the roof of the 
skull, which it nearly reaches in front. Further back it sends 
out two great processes, one superior and the other inferior, at 
right angles to its own plane.’”’? These two processes are said 
to be separated by a deep oval fossa, and comparison with 
Polypterus would indicate that this fossa occupies the position 
‘of the interspace of cartilage that lies between the sphenotic and 
parietopterotic bones above, and the dorsal edge of the as- 
cending process of the parasphenoid below, this cartilage forming 
part of the lateral wall of the trigemino-facialis chamber. ‘The 
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THE AMERICAN JOURNAL OF ANATOMY, VOL. 25, No. 4 
