The Osteology of the Scombridne. 91 



produced. In Scomberomorus the brain chamber is open widely 

 between the alisj)henoids, while in this genus the alisphenoids nearly 

 meet at their middle and almost divide the opening into two parts. 

 The vomer bears a patch of small teeth. 



The nasals and suborbital ring are as in Scomberomorus, but the 

 sclerotic case is thicker and denser than in any other genus. The 

 teeth on the jaws are flat and saw-tooth-like with very sharp finely 

 serrate edges. The anterior part of the premaxillaries project very 

 much in front of the maxillaries to form a sharp beak, though only 

 to a greater degree than in Scomberomorus ; the auxiliary maxillary 

 is well developed. 



The lateral head bones including the hyoid and branchial elements 

 exhibit no departure from the other genera. 



The first two vertebrae bear epipleurals only, the first rib being on 

 the third vertebra. This rib bears on its side, some distance from 

 its base, an epipleural (the succeeding vertebrae are missing). In 

 this respect Acanthocybium differs from all of the other genera, as 

 in the others all of the epipleurals are on the centra. The vertebrae 

 are said to number 32 -|- 34 = 66. 



SAKDA. 



A specimen of Sarda chileusis, Cuvier and Valenciennes, 30 inclies in length, 

 from Puget Sound. 



The cranium is broad and depressed with moderately high thin 

 crests. The supraoccipital crest is carried forward by the frontals to 

 the ethmoid. The temporal crest bends outward from the epiotic 

 and reaches the supraorbital margin above the middle of the orbit. 

 The pterotic crest forms the posterior lateral margin of the cranium. 

 All of the crests are nearly identical with those of the Thunninse. 

 The supraoccipital crest dips down a little farther to the exoccipitals 

 than in Thunnus, but not so much as in Scomberomorus. It does 

 not at all separate the exoccipitals and barely covers the suture 

 between the posterior end of the epiotics. There is a very slight 

 indication of the pit on the lower surface of the cranium that is so 

 pronounced in the subfamily Thunninse, but it in no degree excludes 

 the pterotic from the brain cavity. There are no openings into the 

 brain cavity at the end of the frontals. The myodome opens directly 



