634 INSECTIVORA 



Extinct Genera. — A number of extinct Insectivora from the 

 European Tertiaries more or less closely allied to the Moles have 

 been described, but since our knowledge of most of them is 

 extremely imperfect their precise affinities are in many instances 

 problematical. Of these the Lower Miocene Tetracus is said to have 

 affinity both with Myogale and Erinaceus ; while the forms 

 described as Mysarachne and Echinogale, are considered to connect 

 the present with the two preceding families. Plesiosorex is another 

 Lower Miocene type known only by the mandible, in which there 

 are ten teeth ; it is generally referred to the Myogalince. The minute 

 A mphidozotherium, of the French Phosphorites, is considered to be 

 allied to Urotrichus. 



Family Adapisoricid^e 



This extinct family is represented by the genera Adapisorex and 

 Adapisoriculus, of the lowest Eocene of Rheims, which are regarded 

 as allied to the Soricidw, but somewhat more specialised. In the 

 type genus the formula of the lower teeth is i 2, c 1, p 4, m 3 ; 

 the incisors and canine being proclivous, and the molars (of which 

 the last is small and without a third lobe) quadritubercular. 

 Adapisoriculus is a smaller form with differently shaped molars. 

 Here also may be mentioned the genera Orthaspid other ium and 



Pleuraspidotherium, from the above- 

 mentioned deposits, which are prob- 

 ~" ve ably members of the present order. 

 -/w They appear to have been animals 

 71 s * somewhat smaller than a Hedgehog, 



Fir,. 291.— The last left upper cheek- •, l 1 •*. l 1 l 



.,,„„, ., ,. . " with quadritubercular upper molars 



teeth of Pleuraspidotherium aumoiueri; 1 * A 



from the Lowest Eocene of Rheims. pr, (Fig. 291), and the hinder premolars 



protocone; me, metacone; pa.paracone; more complex than those of the 

 b, cineulum-cusp. (From Osborn.) n • -7 t ,i n i 



Erinaceidcv. In the first-named genus 

 the dental formula is i -§ , c ]-, p -|-, m -f ; the third and fourth upper 

 premolars having one outer column. Pleuraspidotherium has ap- 

 parently only three premolars, of which the third and fourth 

 (Fig. 291) have two outer columns. The humerus in both has 

 no entepicondylar foramen, the femur has a third trochanter, and 

 the astragalus is vertically perforated. 



Family Potamogalid^e. 



Skull with a small brain-case, no zygomatic arch or postorbital 

 process, and the tympanic annulate and not forming a bulla. 

 Upper molars with the cusps arranged in a broad V, and some- 

 what intermediate in structure between those of the preceding and 

 succeeding families. No clavicle ; pubic symphysis ligamentous ; 



