192 ALUS. [Vol. XVIII. 



though I have no intention whatever, in so doing, of definitely 

 homologizing them with the similarly named muscles in other 

 fishes. 



Az lies directly internal to A^, but only covers a part of its inner 

 surface. It extends backward from the distal end of the united 

 muscles through about two thirds the length of that muscle, and 

 downward from the antero-dorsal edge of the muscle through 

 about two thirds its width. It consists of a thin layer, only, of 

 muscle fibers, all of which are inserted on a tendon which forms 

 upon its mesial surface. At the distal end of the muscle this 

 tendon separates into three parts, an upper, anterior one, a middle 

 one, and a lower, posterior one. The upper, anterior tendon 

 (/. Qz mx) runs almost directly forward, internal to the distal 

 end of A^ but external to the dorso-posterior corner of ^ ^ , and 

 then forward internal to and immediately dorsal to the tendon 

 «! la, which arises from the anterior end of A^. Like this latter 

 tendon it lies along the inner surface of the lachrymal, between 

 that bone and the dermal fold that lies between it and the maxil- 

 lary. It is inserted on or near that process of the maxillary that 

 lies on the outer surface of that bone near its ventral edge and 

 close to its anterior end. It may, accordingly, be referred to as 

 the superior maxillary tendon of the adductor muscle. Its gen- 

 eral position seems to indicate that it is the homologue of that 

 tendon of Amia that has its origin on the coronoid process of the 

 mandible and its insertion on the inner, instead of on the outer, 

 surface of the maxillary (No. 4, p. 548). Its insertion, in 

 Scomber, is such that any pull upon it would move the maxillary 

 upward internal to the lachrymal. In one specimen it was double, 

 the lower, stronger part having the ordinary insertion, while the 

 upper, more slender part was inserted on the upper edge of the 

 maxillary near the middle of its length. 



Slightly distal to the base of the superior maxillary tendon a 

 small branch tendon is sent from it downward and backward 

 external to A^^ internal to tendon a^ la, and immediately internal 

 to, or slightly anterior to and parallel to, the small posterior branch 

 of that same tendon. It is inserted, with the latter branch of 

 tendon a^ la, on the outer surface of the articular near its hind 

 end. 



