Nos. IAND2.] ANATOMY OF SCOMBER SCOMBER. 155 



and is only about one half as thick as the ventral arm. It lies 

 along the inner surface of the cartilaginous interspace in front 

 of the metapterygoid, and then along the inner surface of the latter 

 bone, in a shallow but sharply marked triangular depression. The 

 shank of the bone extends forward dorsal to the hind end of the 

 palatine, lying between that bone and the large, middle cartilagin- 

 ous remnant of the palato-quadrate arch. 



The Entopterygoid {ENP) is a large, thin bone, shaped some- 

 thing like the bowl of a spoon. It lies in a nearly longitudinal 

 and horizontal position, its mesial edge being free. The posterior 

 portion of its lateral edge lies against and is firmly attached to 

 the inner surface of the metapterygoid, concentric with and slightly 

 below its concave dorso-anterior edge. In front of the meta- 

 pterygoid the entopterygoid runs forward across the inner sur- 

 face of the dorsal arm of the Y-shaped ectopterygoid ; then along 

 the mesial edge of the dorsal surface of the shank of the latter 

 bone ; and then along the corresponding edge of the palatine. 

 Opposite the interspace of cartilage in front of the metapterygoid, 

 the lateral edge of the entopterygoid is turned downward so that 

 its lateral surface rests against the mesial surface of the cartilage. 

 At its anterior end the bone lies against the ventro-mesial surface 

 of the large middle cartilaginous remnant of the arch. 



The Palatine (F) has a long pointed hind end, which rests 

 against the ventral surface of the large middle cartilaginous 

 remnant of the arch, and, posterior to that cartilage, against the 

 ventral surface of the shank of the ectopterygoid. It bears, on 

 part of its mesial edge, the anterior part of the lateral edge of the 

 entopterygoid. That part of the bone that lies anterior to this 

 long posterior end is stout and broad, and is united by synchon- 

 drosis with the anterior end of the large middle cartilaginous rem- 

 nant of the apparatus. Its anterior end curves downward, and lies, 

 at first, dorsal to, and then external to, the anterior end of the 

 maxillary bone. Its anterior end is capped with cartilage and 

 articulates with the maxillary in a depression on the outer surface 

 of the latter bone. Immediately posterior to the base of this 

 anterior curved end of the palatine, on the dorsal surface of the 

 bone, there is a slightly raised transverse facet of cartilage which 

 may or may not lie on a slight eminence in the bone. It forms the 



