Nos. IAXD2.] JX ATOMY OF SCOMBER SCOMBER. jg^ 



The Levator Maxill.e Superioris, as a muscle, is not found 

 in Scomber. It seems, however, to be represented by certain 

 tendons and ligaments. 



On the inner surface of the antero-dorsal edges of both A-^ and 

 Ao, at about the middle of the length of each muscle, there is in- 

 serted a fibrous or tendinous band. These bands arise, together, 

 from a fibrous membrane that lies internal to the levator arcus 

 palatini, between that muscle and the adductor hyomandibularis 

 and adductor arcus palatini. The external portion or layer of 

 this membrane is distinctly fibrous in character, and can be easily 

 separated from the internal portion or layer, which has more the 

 character of connective tissue. The fibers of the external layer 

 arise from the anterior edge of that thin portion of the hyomandib- 

 ular that lies immediately ventral to its dorso-anterior articular 

 head, or from the lateral surface of that bone near its anterior 

 edge, and also from the dorsal edge and adjoining surface of that 

 process of the metapterygoid that projects backward mesial to the 

 hyomandibular. From this line of origin the fibers run almost 

 directly forward, and disappear on the external surface of the 

 connective tissue layer near the hind edge of the orbit. The con- 

 nective tissue layer has the same posterior origin as the tendinous 

 layer, but its dorsal portion has a large surface of attachment on 

 the lateral surface of the postorbital ossification and on the ex- 

 ternal surface of the united adductor hyomandibularis and ad- 

 ductor arcus palatini muscles, near the origin of those muscles. 

 Antero-dorsally the membrane passes onto the orbital face of the 

 postorbital ossification, filling the hour-glass-shaped depression 

 on that face of that bone, and then becomes continuous with the 

 membranes lining the orbit. The attachment to the adductor 



hyomandibularis and adductor arcus palatini is often so strong 

 that the membrane seems to give origin to a part of the fibers of 

 those muscles. 



From the external, tendinous portion of this membrane the 

 two tendons that have their insertions on A^ and An arise, as do 

 also two small tendons that have their attachment on the anterior 

 edge of the levator arcus palatini. The internal connective tissue 

 portion envelopes the ramus maxillaris inferior trigemini as it 

 passes outward and downward in this part of its course, and 



