8o 



VERTEBRATE SKELETON 



Fig. 83. — Ventral and lateral views of skull of lamprey Petromyzon (Parker). 

 ad, anterior dorsal cartilage; bb, branchial basket; gc, gill clefts; Ic, labial cartilage; Idm, 

 lateral distal mandibular; Ig, lingual cartilage; nc, nasal capsule; oc, otic capsule; on, 

 optic nerve; pc, pericardial cartilage; pd, posterior dorsal cartilage. 



Fig. 84. — Dorsal and lateral views of skull of Myxine (Cole, '05); fine stippling, soft 

 cartilage; coarse stippling hard cartilage; white, hard pseudocartilage; cross-lined, soft 

 pseudocartilage; adp, anterior arch of dental plate; b, brain; bp, basal plates of lingual 

 apparatus; br, branchial arches; cc, cornual cartilages; ch, notochord; dt, median dorsal 

 tooth; elp, external lateral velar bar; /, fenestras; ftp, hypophysial plate; hy, 'hyoid' 

 arch; Up, internal lateral velar bar; //, lateral labial; nc, nasal capsule; nt, cartilages of 

 nasal tube; o, otic capsule; pi, 'palatine' bar; pq, 'pterygoquadrate;' snb, subnasal 

 bar; sps, suprapharyngeal skeleton; t, "trabecula;" 1-4, tentacular cartilages. 



