SKULL TELEOSTOMES 



95 



The cartilaginous visceral skeleton is like that of Elasmobranchs. 

 The mandibular arch (pterygoquadrate and Meckelian) early loses 

 its primitive character. Except in Chondrostei the pterygoquadrate 

 does not function as the upper jaw. Its anterior end may rest on 

 the lower side of the ethmoid plate, or the arch may be incomplete 



here, and its anterior end occa- 

 sionally is a discrete palatine car- 

 tilage (fig. 97). The hinder end 

 of the cartilage is connected with 

 the cranium by a hyomandibular 

 suspensor (is hyostylic) or when 

 the pterygoid rests on the ethmoid 

 plate, is amphistylic. The hyo- 



FiG. 100. Fig. ioi. 



Fig. 100. — Roofing and lateral bones of skull of Amiurus, lower jaw bent laterally 

 (Kindred, '19). ar, articulare; d, dentale; ee, ectethmoid; /, frontal; hm, hyomandibula; 

 /, lacrimal; mpt, metapterygoid; n, nasal; pf, postfrontal; po, postorbital; pop, preoper- 

 culum; q, quadrate; sbo, suborbitals; se, supraeth:noid; so, supraoccipital; sph, sphenotic. 



Fig. ioi. — Floor of cranium of Amiurus (Kindred, '19). bo, basioccipital; ee, ecteth- 

 moid; 60, exoccipital; /, frontal; of, orbital foramen; os, orbitosphenoid; pro, prootic; ps, 

 parasphenoid; se, supraethmoid; sp, sphenotic; sqpt, squamoso-pterotic; v, vomer; 

 2-10, nerve foramina. 



mandibula, usually articulated to the wall of the otic capsule, is 

 generally perforated for the hyomandibular nerve. Its chief ventral 

 connexion is with the quadrate, either directly or with the intervention 

 of a symplectic bone, but there may be a posterior connexion by a dis- 

 tinct inter- or stylohyal cartilage (fig. 74) with the hyale. The hyale 



