the Teeth of O.ten ami S/iefp. 'IJo 



adult lower jaw.s sliowiiiL^ staj^cs towards a (ive-tootlied con- 

 dition, 'riirt-e »ta;^»'3 are clearly rrjircsentcd, as follows : — 

 (I) Jaws with i;;;^ in j)lac«' ; (2) jaws with ,,„!. j in place hut 

 in process of being pushed out, roots partly ah8orbe<l ; 

 (3) jaws with ,„n.^ absent, with slight traces ot" alveolus re- 

 maining. In the vsjx-toothed jaws, /. e. where ^;^2 is present, 

 that tooth shows very little, or almost no, trace of wear, evi-n 

 thouiih all the remaining teeth, including ^73 and ^^i, are 

 consideral)ly worn. One pair of jaws shows p7,i7a in position, 

 but the adjacent premolar is so crowded against it that tho 

 pmTa ii^ only lightly held in its socket, and when lilted out it 

 18 seen that its roots are almost absorbed. 



The possibility of this being a persistent milk-molar was 

 considered, but on cutting away the bone below the tooth no 

 successional tooth was found nor was any crypt present, the 

 bone being quite compact. The tooth was then carefully 

 compared with another ^,^2 J^ud with a deciduous molar 

 (n,.m.a)f a"il was fourjd to agree exactly with the former. 



The left ramus of another lower jaw illustrates the shedding 

 even better, as the anterior root of j;^2 is visible, it having 

 been pushed through the anterior wall of its alveolus. Both 

 the al)ove examples would belong to animals considerably 

 over three years of age*. 



Evidence of the former presence of ^ii^ in other adult 

 lower jaws is furnished by partly obliterated alveoli. The 

 youngest jaw showing the tive-toothed condition is one in 

 which ^;^-i has just begun to wear. 



Two of the Glastoidjury tive-toothed specimens are of 

 further interest, as showing an abnormal condition in the hist 

 true molar (^73). In all true ruminants this tooth is ciiarac- 

 terized by the addition of a third posterior lobe f. This lobe 

 is very small and simple in the gnu, and relatively larger in 

 the Boviihe and ('ervida?. In the Glastoid)ury specimens 

 the third l(d>e of nr.3 '» mmh less develo|)ed than in two 

 specimens of the gnu in the Manchesier i\Iuseum %> 't being 

 represented by a slight loop oidy. The same contlition is to 

 be seen in the lower jaws of a polled skull of a " wild " white 

 cow supposed to be the last relic of a herd formerly kept at 



• Calculated from table in Oweu'a 'Anatomy of Vertebrates,' vol. iii. 

 18G8, p. .V>2. 



+ Tomt'S, ' Dental Anatomy ' (1898, p. 40G, footnote), mentions Neo- 

 trai/uj< hemprichii, a small Abyssinian antelope, as having only two lobts 

 to the third lower molar. 



\ In both tht'st< specimens of ffnn the lower jaws have only five teeth, 

 proTa being absent. 



Ann. «C- Mag. N. Hist. Ser. 8. Vol. w. 20 



