across the mesial surface of the hind end of Meckel's cartilage and is inserted on the mesial surface 

 of the articular ventral to the cartilage. The antero-dorsal tendon turns forward and is inserted 

 on the tendinous formation that Covers the mesial surface of A . 



The mandibular portion, A w , of the adductor muscle, arises wholly on the mesial surface 

 of the mandible, its fibers converging toward and having their insertions on a tendinous formation 

 which largely covers the mesial surface of the muscle. A part of the fibers of this tendinous formation 

 are collected and separated to join the antero-dorsal tendon of A 2 A 3 , the remaihing fibers running 

 directly backward, mesial to all the tendons of the muscle, and having their insertions, as a broad 

 tendinous band, on the preopercular, near its ventral end. In Scomber this latter tendon is inserted 

 by two heads, one on the preopercular and the other on the quadrate, the rami mandibularis externus 

 and internus passing between the two heads of the tendon (Allis, '03, p. 194). 



The levator arcus palatini arises from the roughened lateral corner of the sphenotic. Running 

 downward from there, and spreading slightly forward and backward, it separates into superficial 

 and deeper portions. The superficial portion passes internal to the superficial division, A ls of the 

 adductor mandibulae, between it and A 3 , and then between A^ and A 3 , and has its insertion on 

 the external one of the two flanges on the hind edge of the metapterygoid, and on ad- 

 jacent portions of the hyomandibular and preopercular. Some of its fibers are also apparently 

 inserted in the membrane that covers the external surface of the muscle A 3 . A strong tendon is im- 

 bedded in this superficial portion of the levator, extends from the sphenotic to the metapterygoid, 

 and gives insertion or origin to certain of the fibers of the muscle. The deeper portion of the muscle 

 passes between the two flanges on the hind edge of the metapterygoid and has its insertion 

 on those flanges and on the two membranes that connect the flanges with the anterior edge of the 

 hyomandibular. The ventral end of the internal one of these two membranes has a strong attachment 

 to the internal surface of the dorsal end of the interhyal, and it would seem as if the muscle must 

 have some action on that bone. The two portions of the levator correspond respectively to the 

 superficial and deeper portions of the muscle of Amia. 



5. LATERO-SENSORY CANALS. 



The primary tubes of the latero-sensory canals of Scorpaena, in every case examined, leave 

 the bones to which they are related as simple and single tubes, but, in the overlying dermal tissues, 

 most of them branch repeatedly giving rise to large and often complicated dendritic Systems which 

 open on the outer surface by small and often numerous pores. Certain of these dendritic Systems, 

 belonging to different canals, interanastomose, thus secondarily connecting primarily independent 

 canals, and giving rise to conditions that might, in a superficial examination, be considered as marked 

 irregularities in the course of those canals. 



The main infraorbital canal begins at a group of pores that lies ventro-lateral to the interval 

 between the two nasal apertures. In the two specimens that were carefully examined in this connec- 

 tion, this group was subcircular in outline and contained from 15 to 18 pores; and on one side of 

 one of these two specimens certain of the pores of the group seemed to have anastomosed with cert- 

 ain pores of the second dendritic system of the supraorbital canal, thus apparently establishing a 

 communication between those two canals, the communicating canal passing between the nasal apertures. 

 The group of pores belongs to the first dendritic system of the line, and the trunk of the system enters 



