COLLETTE and RUSSO: SPANISH MACKERELS 



ethmoids) are massive paired bones which form 

 the anterior margin of the orbit and the posterior 

 and mesial walls of the nasal cavity. The lateral 

 portion of each bone extends downward from the 

 middle region of the frontals. The ventral surface 

 of this wall mesially bears an articulating surface 

 for the palatine and laterally another articulat- 

 ing surface for the first infraorbital (lachrymal). 

 The inner walls of the lateral ethmoids come 

 closest to each other at the ventral median line of 



the skull and contact the anterior edge of the 

 parasphenoid. The median half of each lateral 

 ethmoid extends downward about three-fourths 

 as far as the lateral portion and has a large round 

 foramen for the olfactory nerve which is promi- 

 nently seen on the anterior surface. On the dorsal 

 surface, they abut the nasals anteriorly, the fron- 

 tals posteriorly, and articulate with the ethmoid 

 mesially. On the anterior surface, ventral to the 

 foramen, each lateral ethmoid bears a process 



a 



FIGURE 15. — Skulls in lateral view. a. Scomberomorus koreanus, Singapore, 480 mm FL. b. Scomberomorus concolor, Gulf of 



California, 495 mm FL. 



565 



