[67] • THE OSTEOLOGY OF AMIA CALVA. 813 



We are still further impressed with the marked departures from the 

 ordinary fishes made by Alhula in its skull when we come to examine 

 such of the bones of the palatoquadrate arch as I have before me, for 

 which I am also indebted to Professor Gill. One view of this arch I have 

 drawn iu connection with the lateral view of the cranium (Fig. 29) ; the 

 other is an inner view of the same specimen, and awarded a separate fig- 

 ure (Fig. 28). When this arch is snugly articulated with the cranium, 

 the Jiyomandihular {H. M.) is nearly in contact with the postfrontal and 

 prootic for its entire length, or rather as much of it as is opposite these 

 bones ; the same may be said for the remaining elements, the meta- 

 pterygoidal and entopteiygoidal margins meeting the opposed margin of 

 the parasphenoid. Upon an inner aspect this brings the area of teeth 

 found upon the entopterygoid (Fig. 28) opposite and at right angles 

 with the similarly constituted teeth upon the parasphenoid. That teeth 

 should occur exclusively upon the first-mentioned segment is a remarka- 

 ble fact of itself and worthy of special note. Particular attention is invited 

 to the symplectic (Sym.) of Albtila, shown in these drawings, holding as it 

 does a most unique position. Indeed, this may be said of all the bones 

 in this arch ; the metapterygoid is thrown clear to the rear of the quadrate, 

 while in Amia it reaches well beyond that bone. Both the entopterygoid 

 and ectopterygoid are enormously developed. Wedged in between them 

 posteriorly and above is a large mass of bone that appears to be devel- 

 oped oa the part of the first mentioned element. Where they ftieet at 

 the apex anteriorly I find another irregular piece of bone, with a little 

 process on its outer side. This element appears to be separately ossi- 

 fied, but without a complete skull I could not say positively whether it 

 be the palatine or not. It occupies about the proper position for that 

 bone, and, everything considered, it would not surprise me to find it 

 assuming any remarkable shape. A highly developed and prominent 

 semiglobular facet is found on the upper third of the posterior margin 

 of the hyomandibular, for articulation with the operculum. 



Of the cranium of Megalops. — The siDecimen of the cranium of this fish 

 is also from the cabinet of Professor Gill, and from it I have made two 

 drawings (Plate XIV, Figs. 33 and 34) — a direct lateral view and a pos- 

 terior one. The specimen is evidently not a perfect one, though it is 

 the best I could secure for the purpose, and my reasons for choosing it 

 have already been stated above. In this particular specimen the basi- 

 sphenoid is apparently missing, its median plate having been broken 

 off, leaving the points of fracture distinctly visible. Again, either a 

 single parietal plate or a pair of parietals have undoubtedly been lost, 

 and when perfect individuals come to be examined I believe the space 

 existing in Fig. 34 between the supraoccipital and frontals will be 

 properly filled in by such a plate or plates. The rear view of this cra- 

 nium is unaffected by these losses, as none of the bones mentioned 

 would come in sight in this aspect. 



