SOME NEW DEVON I C FOSSILS 28l 



In the dorsal valve the cardinal area is narrow and not long 

 •enough to materially modify the almost circular outline of the valve. 

 The crural processes are conspicuous and divergent and the car- 



^tm&m^ 



Rhipidomella logani 



•dinal process rather diminutive, curved forward, trifid at its end 

 which does not project beyond the hinge. 



In size, a width of 34 mm and a length of 29 mm is an average 

 maximum and the limit of variation in size is not far from this. 



Lower Devonic. Grande Greve, P. Q. 



Rhipidomella lehuquetiana nov. 



Shell small lenticular or subplanoconvex. General outline sub- 

 •circular, a little wider than long. Ventral valve depressed, beak 

 generally obscured or resorbed, umbo depressed ; a broad and low 

 sinus begins in the umbonal region, widens outward and becomes 

 deep on the anterior margin making a strong sinuosity or tongue 

 •extending upward into the other valve. The surface at the sides 

 of the sinus is broad and flat except about the margins where it is 

 more abrupt. 



Surface radii fine, rounded, numerous and subequal and cardinal 

 area moderately high and curved downward at the sides. On the 



