CHAP. II. ] TENERIFFE TO SOMBRERO. 205 
different sizes, the larger about four times the area of the 
smaller. The larger pores are the less numerous: they are 
Fig. 47.—Orbulina universa, D’'Orsiany. From the surface. Fifty times the natural size. 
scattered over the surface of the shell without any appearance 
of regularity: the smaller pores occupy the spaces between the 
larger. The crests between the pores are much less regular in 
I.—14 
