OBJECTIONS AND DIFFICULTIES AND OTHER THF.niMKs I'll 



cusp ontogeny as seen in the molar of the Talp, with which it is 

 identical in pattern, I think one may conclude thai ////'s N/////A r//.s// /* tin 

 paracone [italics ours], the posterior extension representing the metacone, 

 while the internal shelf indicates the position of the future proto- and 

 hypocone." In the moles (genus Ta/jiti, p. 579) the adult upper molars 

 are " mainly tritubercular, but a very small hypocone is present ; the 

 protocone is small, whereas the paracone and metacone, especially the 

 latter, are very large, and show a tendency to become crescentic or 

 V-shaped, . . ." Even in the earliest foetal stages examined two slight 

 prominences were already visible, corresponding to the para- and meta- 

 cones ; these cusps were alone conspicuous in the younger stages, the 

 antero-external or paracone being the largest, though in the adult Mole 

 this is a smaller cusp than the metacone. 



This, the author thinks, shows that the paracone is the first to 

 develop; " tin- i/ifu-nnl protocone appears late, as a low and inward 

 extension of the base of the paracone [Fig. 203], and cannot possibly Ic 

 regarded as the original axis of the tooth" 



The embryogenic succession of the upper and lower cusps is as 

 follows : 



UPPER MOLARS. LOWER MOLARS. 



1. Paracone. 1. Protocol) id. 



2. Metacon^. 2. Metaconid. 



3. Protocone. 3. Hypoconid. 



4. Parastyle. 4. Entoconid. 



5. Hypocone. 5. Paraconid. 



In all these three genera the order of cusp development in the loir<'r 

 molars corresponds substantially with that given by the palreontological 

 theory. 



Thus Woodward confirms Bose and Taeker's. results, and says 

 (p. 584) that "the order of cusp ontogeny is in entire accord with the 

 supposed order of cusp phylogeny as advanced by the supporters of the 

 Cope-Osborn tritubercular theory." 



GROUP II. Tritubercular Molars. The most important form examined 

 by Woodward is the Tenrec of Madagascar, the genus Cciitete*. In the 

 adult the molars have usually been regarded as of columnar and typical 

 trituberculate type, consisting of an elevated internal cusp (protocone) 

 and more depressed external cusps (para- and meta-cone) ; as we shall 

 see, Woodward interprets the homologies of these cusps in an entirely 

 different manner. He observes (p. 573), in foetal development, that the 

 first superior molar is composed of a prominent main cone slightly inclined 

 inwards, this is undoubtedly the cusp determined as protocone of the 

 adult tooth, according to the Cope-Osborn theory, while growing outwards 

 low down from this main dental germ are two smaller ones, a slightly 

 more pronounced anterior cone and a less developed postero-external 



