238 



CO"MPLEX AND COMPOUND TEETH. 



Fig. 57. 



given off near the centre of the tooth, also divide into two 

 before they terminate, as at ??,; and their contour is seen, 

 in the transverse section, to partake of all the undulations 

 of the folds of cement which invest them, and divide the 

 dentinal plates and processes from each other. 



Another kind of complication is produced by an ag- 

 gregation of many simple teeth into a single mass. 



The examples of these truly compound teeth are most 

 common in the class of fishes; but the illustration here 

 selected is from the mammalian class. Each tooth of the 

 Cape ant-eater {Orycteropus\ pre- 

 sents a simple form, is deeply 

 set in the jaw, but without divid- 

 ing into fangs ; its broad and flat 

 base is porous, like the section of 

 a common cane. The canals to 

 which these pores lead, contain 

 processes of a vascular pulp, and 

 are the centres of radiation of as 

 many independent series of den- 

 tinal tubules. Each tooth, in fact, 

 consists of a congeries of long and 

 slender prismatic denticles of den- 

 tine, which are cemented together 

 by their ossified capsules, the co- 

 lumnar denticles slightly decreas- 

 ing in diameter, and occasionally bifurcating as they 

 approach the grinding surface of the tooth. Fig. 57 gives 

 a magnified view of a portion of the transverse section of 

 the fourth molar, showing c, the cement ; cZ, the dentine ; 

 and^j), the pulp-cavity of the denticles. 



In the elephant, the denticles of the compound molars 

 are in the form of plates, vertical to the grinding surface 



TRANSVERSE SECTION OF PART 



OP TOOTH OF 0rycteropu8 



(magnified). 



