COLLETTE and RUSSO: SPANISH MACKERELS 



chial arteries and veins. The ceratobranchials 

 support most of the gill filaments and gill rakers. 

 The first three are morphologically similar and 

 articulate with the posterior ends of their respec- 

 tive hypobranchials. The fourth is more irregular 

 and attaches to a cartilage posterior to the third 

 basibranchial. The fifth ceratobranchial is also 

 attached to the cartilage, has a dermal tooth 

 plate fused to its dorsal surface, and the complex 

 is termed the lower pharyngeal bone. It is covered 

 with small conical teeth that are directed slightly 

 posteriad. 



Epibranchials. — The posterolateral end of each 

 of the four epibranchials is attached to the ends of 

 the first four ceratobranchials. Each epibranchial 

 bears a groove posterodorsally for the branchial 

 arteries and veins. The first epibranchial is the 



longest and bears two processes mesially. The 

 anterior process articulates with the first pharyn- 

 gobranchial, and the posterior process attaches 

 with the interarcual cartilage. The second epi- 

 branchial is similar to the first, but slightly 

 shorter. The anterior end is divided into two 

 processes: the anterior process attaches to the 

 second pharyngobranchial and the posterior pro- 

 cess is coupled with the third pharyngobranchial 

 by way of an elongate cartilage. This process is 

 much more elongate in Grammatorcynus than in 

 Acanthocybium or Scomberomorus. The third 

 epibranchial is the shortest in the series. Lateral- 

 ly, it is attached with the third ceratobranchial; 

 mesially, it is attached with the third pharyngo- 

 branchial. An elongate posterodorsal process is 

 present. This process joins with the fourth epi- 

 branchial. The fourth epibranchial is larger than 



BASIBRANCHIAL 



HYPOBRANCHIAL 



GILL RAKERS 



CERATOBRANCHIAL 



EPIBRANCHIAL 



PHARYNGOBRANCHIAL 



UPPER PHARYNGEAL TOOTH PLATES 



PHARYNGOBRANCHIAL STAY 



FIGURE 36. — Branchial apparatus of Scomberomorus semifasciatus , New Guinea, 510 mm FL. Dorsal view of the gill arches with the 

 dorsal region folded back to show their ventral aspect. Epidermis removed from right hand side to reveal underlying bones. 



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