208 COMPARATIVE DENTAL ANATOMY 



the lower canine closes in the carnivora, quadrumana, 

 etc. 



Diphyodont. An animal having two sets of teeth, 

 both the deciduous and the permanent. 



Distal. Away from the median line of the face (fol- 

 lowing the curves of the dental arch). 



Docoglossa. Plate or chevron formed teeth of mol- 

 lusks. 



Dolichocephalic. Having a long skull, the breadth 

 being less than 75 per cent, of its length. 



Ecderonic. Applied to structures derived from the 

 upper epithelial layers of the derm, as hair, chitin, 

 enamel, etc. 



Elastic Hinge. A device found in fishes and reptiles, 

 by which the teeth can be pushed over and then sprung 

 back to hold prey. 



Enamel. The calcined epithelial tissue covering the 

 crowns of teeth. 



Enderonic. Applied to structures derived from the 

 lower layers of the derm, as dentin. 



Entoconid. The linguo-distal cone or cusp of the pos- 

 terior heel or talon of the lower molars. 



Epithelium. The superficial layer of cells of mucous 

 membranes. A very delicate membrane forming the 

 outer covering of the corium or true mucous membrane, 

 and which enters into the structure of glandular organs. 



Fang. The root of a tooth. 



Fibrous Membrane. The membrane which carries the 

 teeth of sharks and rays. 



Foramen. A passage perforating tissues (usually 

 bone) and transmitting vessels or nerves; e.g., the apical 

 foramen of the root of a tooth. 



Fossa. A round or angular shallow depression in the 



