42 OSTEOLOGY OF SCOMBROID FISHES 



behind the prefrontal. Crnathandon and Chloroscombnts show a marked 

 inclination towards this condition. The pterygoid is developed nearly 

 straight upward, and the process behind the prefrontal is long. In 

 Alectis and Citula the pterygoid is bent farther back, and the process 

 is longer, while in Vomer and Selene it is bent very decidedly back, the 

 process is still longer, and serves as the only attachment of the ptery- 

 goid to the prefrontal. 



The palatine is attached more or less firmly, and with or without a 

 differentiated articular surface, to the front of the prefrontal. The 

 anterior end bears a strong process, which hooks over the maxillary. 



The angular is well developed. In Oligoplites and Vomer the artic- 

 ular completely fills the V-shaped space between the backward extend- 

 ing arms of the dentary. In Scomberoides a small space is unfilled 

 above. In Naucrates and Elagatis a considerable space is unfilled, and 

 in the others the upper arm of the dentary and the upper edge of the 

 articular are only in contact at a small place anteriorly. 



In Oligoplites the dentary is peculiar in having a free wing of 

 bone on the inside, running forward nearly to the symphysis. This 

 wing is present in nearly all other bony fishes, but it curves downward 

 and becomes absorbed near the middle of the mandible. In Scomber- 

 oides this free wing does not run far forward, but from below its lower 

 edge a second wing is developed, which folds downward and runs back 

 to the posterior end of the low r er limb of the dentary, keeping consider- 

 ably above the lower edge of the dentary for its full length. 



In Oligoplites and Scomberoides the maxillary and premaxillary 

 elements are long and slender, and rather closely attached to each 

 other. The premaxillary sends no sharp spur behind the maxillary, 

 though a long inner fold of bone clasps the latter rather closely. A 

 supplementary maxillary is not present in Oligoplites, but in Scom- 

 beroides it is developed, though rather small as compared with those 

 of the other Carangoids. In Trachinotus the maxillary elements are 

 short and loosely attached to each other; the maxillary spur behind the 

 premaxillary is little developed; and the supplementary maxillary is 

 absent. In all of the other forms the maxillary elements are very wide, 

 particularly the posterior end of the maxillary; rather loosely attached 

 to each other, especially in those forms w r ith long premaxillary proc- 

 esses ; they bear upon their upper edges very large supplementary max- 

 illaries, and from the middle of the premaxillary a large triangular 

 spur is sent behind the maxillary. 



The ascending processes of the premaxillaries are very short and 

 triangular in Oligoplites, Scomberoides, Elagatis and Naucrates. In 



