COMPAKATIVE STUDY OP SCOMBROID FISHES. 331 



Tlie ceratobranchiiils are very long, snbequal iu leugtb, more or less cuned 

 upward, and gnwved on the venti-al side. They are narrow in the Scombridao, 

 and narrow and compressed iu the Cybiidro, especially in AcanthocijUum. In 

 tlio ThunnidiD they are more or lc>ss compros.setl at the anterior poiiion, but 

 rather flattened at the posterior. In the Katsuwouidio they are more flattened. 



The epibranchials are short, much curved, and often twisted. They are 

 rather elongated iu the Cybiidre. Tlio curving and twisting of these ossicles 

 are remarkable iu the Scombridse ; but they are rather elongated in the 

 CybiidsG. 



Tlie upper and lower pharyngeals arc broad in the Scombridaj, but iu 

 tlie other scombroid fishes they are naiTow. 



Pectobal Gikdle. 



The pectoral girdle consists of a series of membrane bones, connected with 

 the skull at the upix-r part, foriuiug the anterior border of the abdominal 

 cavity, and at the same time supporting the pectoral fin, it receives the 

 hypaxial portion of the lateral muscle from the cephalic region and some 

 succeeding anterior myotomes. 



The post-temporal is a small forked bone. The dorsal l)ranch is flattened 

 and rests on the epiotic, while the ventral branch is articulated to a meditxn 

 knob of the opistliotic. The ventxul branch is round or oblong in cross- 

 section and hollow at the anterior end. The branch is produced to a short 

 process posteriorly. In the Scombridae we find a long free bifid process 

 between the dorsiil and venti-al branches and exterior to the dorsal branch. 



In Acaiühocijhmm a similar forked auxiliary process is found, partly 

 attached to the exterior side of the dorsal branch. Iu the other forms of the 

 CybiidiO, the auxihary process is not found, and the cross-section of the 

 ventral branch is oblong. The dorsal and ventral processes are connected 

 at their root with a thin lamella. The posterior lamellar portion of the boue is 

 produced forward very httle. The interior ridge, continuous to the ventral 

 branch ends with a free point in the genus Sarda. 



In the Plecostei the post-temporal is well developed, and the interior ridge 

 continuous to the ventral process ends with a free process. In the Thuuuidas 

 the ventral branch is thick and rounded in cross-section. The lamellar portion 



