Nos. IAND2.] ANATOMY OF SCOMBER SCOMBER. 131 



infrapharyngobranchial, the postero-mesial end articulating with 

 the third infrapharyngobranchial. Slightly distal to the triangular 

 articular head of the piece, on the postero-mesial edge of the bone, 

 there is a strong, angular or triangular process, directed at first 

 postero-mesially, perpendicularly to the shank of the bone, and 

 then distally parallel to that shank. The hind end of the proc- 

 ess gives insertion to the third interarcualis dorsalis; its anterior 

 edge giving insertion to the external levator of the second arch. 

 Immediately distal to this process the bone has its narrowest por- 

 tion. The dorsal surface of the bone is deeply grooved, the 

 groove running forward to the proximal edge of the postero-mesial 

 process, where it disappears. 



The Third Epibranchial (EB, III) has a short, straight 

 shank, and much enlarged, somewhat triangular proximal end, 

 which lies nearly at right angles to the shank. Both ends of the 

 bone are capped with cartilage, the proximal articular head articu- 

 lating with a process of the third infrapharyngobranchial that pro- 

 jects backward onto the dorsal surface of the adjoining fourth 

 infrapharyngobranchial. This process of the third infrapharyngo- 

 branchial is capped with cartilage, the large articular surface thus 

 formed lying directly dorsal to, and extending across, the line 

 that separates the third infrapharyngobranchial from the fourth. 

 At the angle between the shank and the proximal articular head 

 of the third epibranchial, from the postero-mesial edge of the 

 bone, there is a strong, irregular process, which lies approximately 

 at right angles both to the shank of the bone and to its enlarged 

 articular head. It is directed backward, mesially and slightly 

 upward. Its outer end is large and capped with cartilage; and 

 it articulates with a process on the antero-lateral edge of the fourth 

 epibranchial. Its anterior edge projects somewhat upward as a 

 sharp ridge which gives insertion to a part of the third obliquus 

 dorsalis. The outer end of the process gives insertion to the ex- 

 ternal levator of the third arch ; and from the lateral end of its 

 outer, or posterior edge there is a process directed backward and 

 laterally, approximately parallel to the shank of the piece, which 

 gives insertion to the fourth interarcualis dorsalis. The outer end 

 of the process articulates with the antero-lateral edge of the fourth 

 epibranchial. Between the hind edge of the process and the edge 



