28 THE SESAMOID ARTICULAR 



Meckel's cartilage and against the ectosteal plate of the articular. In 

 Scomber it is on the upper surface of the cartilage. In Scomberomorus 

 it is somewhat between the cartilage and the articular. In Sarda, Gym- 

 no sar da and Acanthocybium it likewise is between but more above the 

 cartilage. In all but Acanthocybium it is in contact with the end of the 

 endosteal process, but in none of them is it on the upper surface of the 

 process. 



THE CARANGID^:. 



Selene oerstedii, Naucrates ductor, Lichia glauca, Alectis ciliaris, 

 Citula dorsalis, Chloroscombrus chrysurus, Caranx pisquetus, 

 Megalaspis cordyla. 



The sesamoid articular is covered more or less completely by the 

 endosteal process and Meckel's cartilage as viewed from the side, lying 

 with its outer surface against the ectosteal plate. 



Trachurops crumenopthalmus, Nematistius pectoralis, Elegatis bipin- 

 nulatus, Decapterus punctatus, Trachurus mediterraneus. 



The sesamoid articular is as in Selene et. al. but more anteriorly 

 placed, and very slightly if at all in contact with the endosteal process. 

 In Trachurus it is thinner and more broadly connected with the ectosteal 

 plate than in the others. 



Vomer setipinnis, Scomberoides toloparah, Gnathanodon speciosus. 



In these the sesamoid articular is more on top of the endosteal 

 process and Meckel's cartilage than behind them. In Vomer it is much 

 less broadly connected with the ectosteal plate than in the other two. 



OTHER SCOMBROID FISHES. 

 Leiognathus fasciatus. 



The lower part of the articular is folded inward as well as abruptly 

 thickened, thus forming a wide longitudinal shelf. The endosteal process 

 is obscure. The sesamoid articular is a wide, thin plate (5 mm. long in a 

 mandible 27mm. long), closely attached horizontally to the longitudinal 

 shelf. Meckel's cartilage is a very thin rod which disappears under the 

 sesamoid articular. To the upper, flat surface of the sesamoid articular 

 two equally stout tendons are attached: one a little behind its middle, 



