14 



DESCRIPTION OF THE PLATES. 



PLATE 48. 



Fig. 1. — A row of intermaxillary teeth of 

 the Hypostoma. Fig. 2. Four intermax- 

 illary teeth of the Rhynelepis. Fig. 3. 

 Five intermaxillary teeth of the Acanthi- 

 cus. Fig. 4. Reduced view of the bones 

 of the upper and lower jaws of the Sudis 

 gigas ; a, intermaxillary ; b, maxillary ; 

 c, palatine ; d, pterygoid ; e, vomer ; /, 

 premandibular ; g, articular ; h, suran- 

 gular ; i, angular. Fig. 5. Teeth of the 

 upper jaw of Sudis gigas: f, f, basi- 

 sphenoid. Fig. 6. Lingual bone with 

 anterior and posterior groups of teeth, 

 (Sudis gigas). Fig. 7. Dental system of 

 Osteoglossum : a, intermaxillaries ; b, 

 maxillaries ; c, palatines ; d, vomer, e, 

 lingual bone. Fig. 8. Teeth in situ of 

 Serrasalmo. Fig. 9. Intermaxillary, max- 

 illary, palatine, vomerine, premandibular, 

 and lingual teeth of a salmon. (Salmo 

 salar.) Fig. 10. Similar view of the 

 teeth of Myletes. Agassiz* 



PLATE 49. 



Fig. 1. — Intermaxillary teeth of a Parrot- 

 Fish (Scarus muricatus). Fig. 2. Skull 

 of a Scarus with two of the intermaxil- 

 lary teeth, on each side, prominent and 

 pointed. Fig. 3. Premandibular bone, 

 cleft vertically near the symphysis, of 

 Scarus muricatus: a, one of the last- 

 formed denticles ; b, dentiparous cavity. 

 Original. 



PLATE 50. 



A longitudinal section of a single denticle 

 of the Scarus muricatus : magnified. 

 Original. 



PLATE 51. 



Fig. 1. — Vertical section of an upper pha- 



* Spix, risces Brdeilienses, 4to. 



ryngeal bone and teeth of Scarus mu- 

 ricatus. Fig. 2. Dentigerous surface of 

 the two upper pharyngeal bones of ditto. 

 Fig. 3. Lower pharyngeal bone and teeth 

 of ditto. Original. 



PLATE 52. 



Fig. 1. — Vertical section of five pha- 

 ryngeal teeth of Scarus muricatus, nat. 

 size. Fig. 2. Section of a single tooth 

 magnified 150 linear diameters, (reduced 

 view). a. Osteo-dentine : b. dentine : 

 c. enamel: d. cement. Fig. 3. Termi- 

 nation of a single dentinal tube, mag- 

 nified 700 linear diameters. Original. 



PLATE 53. 



Fig. 1. Portion of under jaw of the Barra- 

 cuda Pike (Sphyrcena Barracuda), a, a, 

 orifices of concealed alveoli of successional 

 teeth. Fig. 2. Longitudinal section of 

 apex of one of the teeth, magnified 250 

 linear diameters. Original. 



PLATE 54. 



A longitudinal section of a fossil Sphyrenoid 

 Fish (Sphyrcenodus priscus, Agassiz ; Dic- 

 tyodus, mihi) : magnified 150 linear diame- 

 ters. 



PLATE 55. 



A part of a longitudinal section of the 

 tooth of the Saurocephalus lanciformis ; 

 magnified 250 linear diameters. A de- 

 tached tooth and two in situ are added 

 of the natural size. Original. 



PLATE 56. 



Fig. 1. — A portion of the lower jaw of 

 the Angler (Lophius piscatorius) . a, a. 

 Outer row of teeth : b, b. Inner row 

 of teeth ; one of these is bent down, 



