1 2 Memoir Sears Foundation for Marine Research 



of the mouth; the premaxillaries, and often the maxillaries, are attached to the skull 

 with varying degrees of firmness in different groups. The palatopterygoid-quadrate 

 elements of the upper jaw-complex are articulated anteriorly with the ethmoid (nasal) 

 region of the skull and are suspended posteriorly (usually via a symplectic bone) from 

 the hyomandibular arch ; but they are not fused solidly anywhere with the lower surface 

 of the skull, except in one known case.'* A bony gular plate is present in the chin region 

 between the two branches of the lower jaw in the Amiidae and Elopidae, and there is 

 a pair of such plates in the polypteroids. The cheek region of the skull is without 

 squamosal bone. 



In most of the bony fishes, the jaw teeth, if present, are separate from each other, 

 and their substance is separate from that of the jaw except for those in which it is 

 cemented basally "by bony substance which is resorbed when the tooth is shed" (45: 

 272 — Goodrich). 



A persistent spiracular opening is present in only a few (polypteroids, some aci- 

 penserids, and polyodontids). The nasal cavities end blindly in the great majority; 

 however, in Jstroscopus {22: 993; 23'. 348-365; J: 371) and in Uranoscopus (original 

 observation) of the Uranoscopidae they open both inwardly to the mouth and out- 

 wardly to the exterior, as they do in various members of the eel tribe as well (j: 371); 

 this is suggestive of similar conditions among the Dipnoi (lungfishes), but the two 

 are probably not homologous. Gill rakers, present in the great majority,^^ vary widely 

 in number. Branchiostegal rays, though present in the great majority, are lacking in a 

 few (sturgeon and paddlefish tribes, polypteroids, and Lyomeri). 



The endoskeletal support of the pectoral fin consists typically of one or two series 

 of short basal radialia, either in parallel or in more or less fan-like arrangement; these 

 radial ia articulate with the pectoral girdle directly in most Actinopterygii but indirectly 

 in a few. The endoskeletal support of the pelvic fin is essentially similar, but here the 

 radialia are greatly reduced. The dorsal and anal fins are supported basally by a single 

 series of more or less rod-like radialia; in most, the rays of both dorsal and anal fins 

 are equal in number to the basal radialia, but in both acipenserids (sturgeons) and 

 polyodontids (paddlefishes) the rays of both fins are much more numerous than the 

 radialia; among the polypteroids, while the dorsal rays more or less equal the number 

 of radialia, the anal rays are much more numerous. 



The outer surface of the scales (if any) consists of a simple calcified layer in most, 

 but is enamel-like in appearance (ganoine) in a few. 



or are very small in some members of the Argentinoidea [86: 605-614, pi. 11; 62: 30-31, figs. 9-11); and the 

 Monognathidae (an aberrant family of lyomerids) have no upper jaw-complex at all (5: 533-540, figs. 1-4; 6: i, 

 5, figs. 2, 3). ^ 



34. In the argentinoid genus Macropinna, according to Chapman {15: 273), the palatoquadrate complex is "immov- 

 ably synchronized" with the occipital portion of the skull. Among the Ophiocephalidae and Symbranchii, the 

 metapterygoid bone (part of upper jaw-complex but not forming part of gape) is in contact with the sphenotic 

 bone, which is part of the posterior rim of the orbital capsule of the skull. For references, see Berg {4: 306, 471). 

 For an explanation of the mode of suspension of the upper jaw that is typical of ray-finned fishes, see especially 

 Parker and Haswell {$g: 243, fig. 207; 244). 



35. Lacking in some members of the Cetomimidae {61: 20-32), in the Istiophoridae, and perhaps in some others. 



