DESCRIPTION OF THE PLATES. 



13 



Vetula. Fig. 3. Upper and lower jaws 

 and teeth of a Gilt- Head (Chrysophrys 

 australis). Original. 



PLATE 43. 



Fig. 1. — Vertical section of a tooth of 

 Microdon radiatus magnified 50 linear 

 diameters. Fig. 2. A section, in the 

 direction indicated by the lines, of an 

 incisor of Sargus rufescens : «, dentine ; 



b, modified enamel : c, clear intermediate 

 space (calcified preformative membrane) ; 

 d, osteo- dentine. Original. 



PLATE 44. 



Fig. 1. — Four of the premandibular teeth 

 of the Acanthurns nigricans magnified 

 30 linear diameters : a reduced view. 

 Original. Fig. 2. A vertical longitudi- 

 nal section of the continuous parts of four 

 of the lamelliform teeth of the Phyllodus 

 toliapicus: a, the osseous basis; b, the 

 dentine ; e, the enamel. Original. Fig. 3. 

 Two of the teeth of a Chcetodon : a, front 

 view of the subtransparent tooth ; b, side 

 view of the longitudinal section, showing 

 the pulp- cavity (v. Born)*. Fig. 4. A ver- 

 tical section of the right intermaxillary 

 bone of the Chrysophrys : a, the posterior 

 oval triturating dental plate"; b, the germ 

 of its successor in the alveolus of reserve ; 



c, the rudiment of the third generation of 

 the same tooth ; the line from letter b 

 shows the tract of communication, still 

 open, between the second and third alveo- 

 lus. (Cuvier and Vol.) Fig. 5. The 

 tooth of a Pike in progress of formation, 

 with its capsule and a portion of the sur- 

 rounding gum : a, the apex of the calcified 

 tooth ; b, the external membrane of the 

 gum reflected around the base of the 



* Heusingt'i's Zeitschrift, Bd. i. 1827. 



tooth to form its capsule ; c, the dentinal 

 pulp ; d, the nerve of the pulp (v. Born) ■ 

 Fig. 4. The right premandibular bone of 

 a young Pike, dissected to show the 

 nerves of the tooth, viewed from the inner 

 side: a, branches of the third division of 

 the fifth pair of nerves; b, branchlets of 

 the same to the integuments on the out- 

 side of the jaw ; c, twigs for the teeth ; 

 one is sent off to each tooth; d, branch 

 which perforates the bone, supplies that 

 part and the outer integuments, (v. Born.) 



PLATE 45. 



Fig 1. — Inside view of the intermax- 

 illary bone and teeth of a "Wrasse (La- 

 brus, Linn., Cossyphus, Cuv.) Fig. 2. 

 Inside view of premandibular bone and 

 teeth of ditto. Fig. 3. Pharyngeal bone 

 and teeth of the southern Gilt-Head, 

 (Chrysophrys australis). Fig. 4. The 

 two upper pharyngeal bones and teeth of 

 a large species of Wrasse (Labrus). 

 Fig. 5. Pharyngeal bone and teeth of 

 Chrysophrys aurata. Fig. 6. A vertical 

 section of a pharyngeal tooth of a Chry- 

 sophrys, Original. 



PLATE 46. 



Fig. 1. — A vertical section of a pharyn- 

 geal bone and teeth of a Labrus : a, teeth 

 in use; b, successional teeth, Fig. 2. 

 A magnified view of a similar section 

 of a single tooth and its socket of a La- 

 brus. Original. 



PLATE 47. 



Fig. 1. — Upper surface of the dental plate 

 of an extinct Ganoid Fish (Phyllodus). 

 Fig. 2. Under surface of the same. 

 Fig. 3. Upper surface of a median denti- 

 gerous bone of the Pisodus Owcnii. Ag. 

 Original. 



