PLATE XX. 



Biddulphia pulchella. Gray., p. 4-70. 

 Biddulphia aurita (Lyngb.), Breb., p. 471. 

 Biddulphia aurita, var. minima-, p. 472. 

 Biddulphia aurita, var. minuscula, p. 472. 

 Biddulphia Rhombus (Ehr.), Wm. Sm., p. 472. 

 Biddulphia Rhombus, var. trigona, p. 472. 

 Biddulphia Baileyii, Win. Sm., p. 473. 

 Biddulphia granulata, Roper, p. 473. 

 Biddulphia la? vis, Ehr., p. 474. 

 Biddulphia laevis, forma minor, p. 474. 



