484 PLEROTES. 



lrin)i<^ular, outer and inner ridges po complelcly fused as to leave 

 scarcely any trace of a median groove. p\ ra', p^. m,. and m^ very 

 low, crown flattened, with no trace of the usual cusp-like elevations 

 of the outer and inner ridges ; upper teeth with a slight but quite 



^-<4,>=>*^ 



Fig. 2%.— Plfrotes OM(hie*a, J ad., type of speoies (Lisbon Musevuii). 

 Upper and middle row I (linear), lower row }. 



distinct, lower teeth with a scarcely detectahle remnant of the 

 median longitudinal groove, ra, rudimentary, subequal to an upper 

 incisor, situated considerably behind m„, and with no upper tooth 

 to act against. 



Falate-ridf/es (fig. 20 B). — Palate crossed by eight ridges forming 

 regular curves from side to side (an indistinct trace of a ninth 

 ridge at esireme posterior border of palate); six anterior ridges 



