290 SHUFELDT. [Vor=dil: 
which case it would be a pterotic. I would have to dissect a 
young fish to decide this point. These processes are very 
conspicuous upon posterior view, and of course Grammicolepis 
can show nothing like them. 
Pomacanthus paru has another condition present, not seen in 
any of the other forms alluded to above. Just posterior to the 
prootic, and above the basioccipital and parasphenoid in the 
cranium of this fish, on either side, we find a subelliptical fora- 
men, with its major axis placed longitudinally, of no inconsider- 
able size, through which we can easily observe the movable 
otolith (Fig. 10, ot?). 
Figure ro. — Left lateral view of the cranium of Pomacanthus paru; life size, by 
the author, from specimen 12,770 of the Smithsonian Institute. Lettering as before, 
with o@/, ofolith, and c.v., first vertebra of the spinal column, which is here codssified 
with the basioccipital. 
Before concluding our comparison of these crania, we must 
note another point in the cranium of Pomacanthus, and this is, 
the ossified orbitosphenoids and the ethmoid meet in the middle 
and interorbital line, immediately beneath the frontals. 
We have already fully described above, the relation of these 
several elements in the subject of this paper, and how any such 
condition is entirely absent in Caranx. This latter form, how- 
ever, may have the ethmoid extended backwards in cartilage, 
which material may be missing in these dried preparations. 
