The Osteology of the Scomhriclse. 



89 



with the hypiiraL The vertebral elements are arranged as in 

 Scomber, as are the other elements with the above exceptions. 



SCOMBEROMOKUS. 

 A speciiiien of Scomberomorus sierra, Jordan and Starks, 24 inches in length, 

 from Mazatlan, Mexico, and tlie liead of a siiecimen of S. maculatus (Mitchill), 

 18 inches in length, from Chesapeal-ce Bay. 



This genus differs from Scomber in having the supraoccipital crest 

 carried forward by the ffontals to the ethmoid, and in having the 

 cranium deeply concave for its full leng-th on each side of the crest. 

 The temporal crests are directed straight forward as in Scomber, but 

 they are not interrupted above the eyes by a transverse ridge. They 

 nearly reach to the ethmoid, and anteriorly between them and the 

 pterotic crests are developing small auxiliary crests as in Scomber, 

 Imt situated farther forward. ' The pterotic crest extends forward to 

 above the middle of the eye. The myodome opens posteriorly through 

 a wide longitudinal foramen. 



The supraoccipital crest extends down over the exoccipital suture 

 more broadly than in any other genus except Acanthocybium, though 

 it is not at all interposed between them. The exoccipitals broadly 

 meet for their full length above the basioccipital. Their vertebral 

 condyles are large and slope back over the basioccipital as usual. 

 The pterygoid docs not end in a sharp spine posteriorly. The eth- 

 moid is forked or concave in front to receive the premaxillary proc- 

 esses. The opisthotic is interposed between the exoccipital and 

 pterotic, so that as much of it is on the superior surface of the 

 cranium as on the inferior. The lower limb of the posttemporal is 

 attached directly, or without the intervention of a ligament, to its 

 superior surface rather than to its posterior edge. 



The suborbital ring is incomplete; the preorbital is well developed 

 and there are two small suborbital plates, the second developed as a 

 small thin suborbital shelf. The rest of the ring is made up of the 

 thick scales that cover the cheek, which are slightly turned inward 

 at the border of the eye ; they carry no sensory tube. A small thin 

 Y-shaped supratemporal bone is present bearing a branched sensory 

 tube just under the skin. The nasals are wide bones attached for 

 their full length to the side of the frontal and ethmoid, and do not 

 project at all beyond the latter. 



