Nos. IAND2.] ANATOMY OF SCOMBER SCOMBER. 



i^i 



enters the eyeball. As it passes across the outer edge of the orbital 

 opening of the eye-muscle canal it has, as in Amia, and as already 

 stated, a short and delicate commissural connection with the 

 internal carotid. 



The arterial connections of the demibranch of Scomber are thus, 

 so far as they were traced, exactly similar to those of Sal mo, as 

 given by Maurer (No. 45, p. 231, 243), excepting in that the 

 efferent artery of the demibranch in Scomber has a commissural 

 connection with the internal carotid not found by Maurer in Salmo, 

 and that the arteria hyoidea passes upward in front of the hyo- 

 mandibular instead of traversing it. The connections are also 

 exactly the same as those in 12 mm. larvae of Amia, as will be fully 

 set forth in a work I have now in progress and that will un- 

 doubtedly be published before the present one. 



It is to be noted that the dorsal end of the arteria hyoidea of 

 Scomber lies between two posterior processes of the metaptery- 

 goid, in what might be considered as a grooved portion of the hind 

 edge of that bone ; that is, it has to the metapterygoid what might 

 be considered as the relation of a branchial artery to its arch. 



5. IMandibular and Palatine Arches. 



The palato-quadrate apparatus of Scomber contains five bony 

 elements, the mandible three. In the palato-quadrate three inde- 

 pendent remnants of cartilage are found, in addition to three 

 terminal cartilaginous caps ; in the mandible a rod of cartilage, 

 representing Meckel's cartilage, and one articular cap. 



The Metapterygoid {MP) is somewhat triangular in shape, 

 with one convex edge, one concave one, and one that has both 

 convex and cancave portions. The convex edge of the piece 

 forms its inferior edge, and is everywhere bounded by the posterior 

 cartilaginous remnant of the apparatus. The concave edge is pre- 

 sented antero-dorsally ; the third edge of the piece being presented 

 posteriorly, its dorsal portion being convex, and its ventral portion 

 concave. These last two edges of the element form with each 

 other a sharp angle, the dorsal end of the bone here curving up- 

 ward and forward and tapering to a point which is alwa^'S capped 

 with cartilage. This part of the element lies external to the 

 thin, anterior portion of the hyomandibular. Its posterior edge 



