INSECTIVORES. 417 



incisors are very small ; none of the succeeding teeth present the 

 form and size of a canine ; the last three teeth are multicuspid, and 

 are true molars. In the lower jaw all the teeth anterior to the true 

 molars are small and simple. 



The teeth in the lower jaw of a species of Water-mole, as large 

 as a Hedgehog, which has become extinct in England, present a 

 close resemblance with those of the Mygale ; the true molars have 

 square, quinque-cuspid crowns, but are distinguished from the teeth 

 of all known recent Insectivora by the presence of a minute tubercle 

 at the bottom of the outer vertical fissure of the crown. I have 

 called this extinct genus Pal(Eospalax.{\) 



The typical Shrews always manifest their Rodent analogy 

 by the superior size of the anterior pair of incisors in both 

 upper and lower jaws ; in the latter the great incisor is uniformly 

 succeeded by two small and three large multicuspid molars ; but 

 in the upper jaw the number of small premolars varies, and there 

 is generally a fourth true molar of small size. The sub-genera of 

 Shrews are chiefly based upon the form of the large incisors, and the 

 numeral variations of the dentition of the upper jaw. In the common 

 Shrew (Sorex araneus of Linnseus, PI. Ill, fig. 2) there are four true 

 molars and three small teeth between these and the anterior incisor ; 

 this tooth has a pointed tubercle at the back of the base of the 

 crown. The long procumbent incisor of the lower jaw has the trench- 

 ant superior margin entire. In the Sorex (Amphisorex) tetragonurus 

 (PI. 110, fig. 4) the edge of the lower incisor is notched ; the large upper 

 incisor appears bifurcate from the great development of the posterior 

 talon ; five small teeth progressively decreasing in size, intervene 

 between the upper large incisor and the true molars. In the Sorex 

 (Hydrosorex) Hermanni the trenchant edge of the lower procumbent 

 incisor is entire ; there are four small teeth between the large anterior 

 incisor and the true molars in the upper jaw, as in the great Sorex 

 indicus, but the three first are sub-equal and the fourth very minute ; 

 there is a fourth small true molar above. The enamelled tips of 

 the teeth of the species of Amphisorex and Hydrosorex are stained 

 (1) " History of British Fossil Mammals," p. 25. 



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