90 TRANSACTIONS OF THE AMERICAN PHILOSOPHICAL SOCIETY 



TABLE 1— Continued 



(d) "Endopterygoid" or meso- 

 pterygoid ( = true pterygoid 

 of tetrapods) 



(e) "Pterygoid" (— ectoptery- 



goid of tetrapods) 



covered ventrally by Dentigerous palatine 11 



originally covered ven- 

 trally by Dentigerous part of ectopter>goid 



Primary lower jaw ( = Meckel's car- 

 tilage) 

 Proximal part (Articular) 



Distal part (wanting in teleosts); 



covered inferiorly by 

 covered laterally by 



overed dorsally by 

 covered mesially by 



functionally replaced by 



C Endohyal 

 Hyomandibular 



Symplectic ( = distal segment of 

 hyomandibular) 



Interhyal ( = ? stylohyal of tetrapods) 

 Epihyal 



Ceratohyal 

 Hypohyal 



Glossohyal ( -= basihyal of elasmo- 

 branchs, Ridewood) 



D Endobranchial 



Pharyngobranchials 1, 2, 3, 4 

 Epibranchi^ls 1, 2, 3, 4 

 Ceratobranchials 1, 2, 3, 4, 5 

 Hypobranchials 1, 2, 3, 4 

 Basibranchials 1, 2, 3 



covered by 



(2) Hyoid 

 bearing posterolaterally 



covered laterally by 



bearing dorsally 

 bearing ventrally , 



covered dorsallv by 



Angular (usually reduced in teleosts) 

 Dermarticular (often fused with articular) 



Surangular (usually lost in teleosts) 

 Prearticular ("splenial") 



Sesamoid articular (a "tendon bone" marking insertion of 

 part of adductor mandibulae muscles (Ridewood, 

 Starks)) 



Coronoids ("splenial"; usually lost in teleosts) 



Dentarj- (the dominant dentigerous element in teleosts) 



Infradentaries 1, 2, 3 (anterior and posterior splenials of 

 crossopterygians) 



C Dermohyal 

 Region 



Opercular 

 Subopercular 



Preopercular (bearing the hyomandibular branch of the 

 lateral-line canals) 



Interopercular 

 Dentigerous plate 



Branchiostegal rays (10 in Salmon, 34 in Tarpon, 6 in many 

 Acanthopts. — Hubbs.) 



Dentigerous plate 



Urohyal (a "tendon bone" arising in the septum between 

 the longitudinal throat muscles) 



D' Dermobranchial 



(3) Branchial Region 



The gill chamber is covered laterally by the Opercular, 

 Subopercular and Interopercular and branchiostegal 

 rays, all derived from the opercular fold 



"Upper Pharyngeals" (= dentigerous plates on fourth 

 pharyngobraachials) 



covered dorsally by 

 covered ventrally by 



"Lower pharyngeal" ( = dentigerous plate on fifth cerato- 



branchial) 

 Dentigerous plates 



Gular plate of amioids, etc. 



