Teeth in the Centttidie. 527 



Microgale Jhhsoni. 



Stage I. All molars functional. In the upper jaw the whole 

 of the milk-teeth are still present, with the exception of 

 I.d.3, which on each side is replaced by its successor. 

 The two /. 1 commence to protrude behind the I.d. 1. 

 In the lower jaw /.(/. 1, I.d. 3, J\d. 3 on each side, and 

 P.d. 1 on the right are replaced. 



Stage II. Like I.; in addition, however, P.d.l is also re- 

 placed in the upper jaw, and the same tooth on the left 

 in the lower. Among the adult sj)eciinens, z". e., those 

 in which the milk-dentition is rej)laced completely, there 

 are several in which the skulls are shorter than that of 

 this stage. 



Stage III. Like IT., with the trifling difference that P.d. 1 

 ivf. is replaced on each side. 



Stage IV. In the upper jaw P.d. 1, P.d. 3, and T.d. 3 on both 

 sides, and I.d. 1 on the right are replaced ; in the lower 

 jaw P.d. 1, P.d. 3, I.d. 3, and I.d. 1 . I.d. 2 is about to 

 be shed above and below. 



Microgale Coioani. 



Stage I. All milk-teeth are in situ and functional. M. 2 is 

 almost completely through the gum, and M. 3 is com- 

 mencing to protrude. 



Stage II. Milk-teeth as in 1. All three molars functional. 

 In the upper jaw /. 3 on the left is beginning to protrude 

 behind and on the inside of I.d. 3. 



Microgale Thomasi. 



Stage I. All milk-teeth functional : no trace of their succes- 

 sors yet visible. M. 3 not yet completely protruded. 



According to what has been stated above, in Oryzoryctes 

 the milk-teeth are replaced in the following order: — I.d. 3, 

 I.d.\,Ld.2,P.d.'S, P.d.l, P.d. 2, C.d. In Microgale the 

 replacement of I.d. 1 sup. and I.d. 2 takes place later, in conse- 

 quence of the powerful development of its root. According to 

 what has been stated in the case of Oryzoryctes tetradactylus, 

 the milk-teeth appear in the same order as their successors. 



In connexion with the foregoing a few remarks may here 

 be introduced on tooth-form ulee and tooth-change in the 

 Solenodontidfe and Potamogalidaj, which are closely allied 

 to the Centetidse. 



