Dei'elo]>ment of the Teeili of the Soricidge. (511 



8. The occurrence of lingual buds reliitcd to several perma- 

 nent teeih, and especially to tlie large incisors in both 

 jaws, shows that there is material enough for producing 

 a postpcrmanent dentition. 



1). The result of the above investigation may be expressed 

 through the; foHowiug formula: — 



1' I- 1' I' !■ (' P' P- P^ P' M' M^ M' 



Id- Id' Id '' Cd Pd' Pd- Pd' Pd' 



Id, — Pd, Pd, — Pd. 



I. 1.1,1. (C) P, P. (P,)P,. 



The functional set of teeth consists of : — 

 PPP pt p-i pa p» M^ M" M^ 



II I', P, Mj M, M;,' 



Neomys (Crossopus) fodiens. 



The germs of the 2>ermane7it teeth. 



Foetus: hochj-lenfjth ahoui 17 mm. 



The upper jaw. 



1 have not yet been able to procure more than one stage 

 of Neomys, and the specimens are rather old. 



The tooth-band is continuous as in Sorex, the two halves 

 being connected in the middle. The counection with the 

 l)uccal epithelium is about to be lost. 



The part of the tooth-])and situated in front of the large 

 functional incisors is well developed, and there is a bud-like 

 swelling on each side, which might be a tooth-germ, in such 

 case j)robably the homologue of 1" in Sorex. For want of 

 younger foetal specimens 1 cannot at present pronounce a 

 definite opinion on this structure. 



In Neomys, at least at this stage, there is no trace of the 

 anterior swelling found in Sorex which I have designated 

 as 1^ 



The large functional first incisor, designated I' as the 

 corresponding one in Sorex, presents an advanced stage of 

 development, its tooth-germ being bell -shaped. The other 

 two iucisorsj I' and 1', are about to pass into the cup-shaped 

 stage. 



On the lingual side of P the free deep end of the tooth- 

 band is swollen and bud-like. 



There is no trace of a canine in the uj)per jaw. A distinct 

 germ of this tooth being present in the lower jaw — as will be 



