48 TOILERS IN THE SEA. 



these may be added various irregular forms, long 

 flexuous lobes packed side by side, or chrysalis-like 

 forms with two or three longitudinal series of 

 chambers packeol closely like wedges, some regularly 

 and others irregularly. In fact, there is such a 

 multiplicity of forms (figs. 5, 6, 7, 8, 9) that they might 

 be called polymorphous, and even a single species, 

 as now understood, may include 

 individuals which diverge re- 

 markably from each other. It 

 would be almost an exaggera- 

 tion to say that no two indivi- 

 duals are exactly alike, but one 

 is almost tempted to think so, 



FIG. 7.-ENTOMOSTEGA. >" P^HCC of SUch 3. multipli- 



city of form. 



One important result of deep-sea dredging has been 

 to exhibit the relationship of the floor of the sea to 

 the chalk deposit of the " dear white cliffs of Dover." 

 " The dredging at 2,435 fathoms at the mouth of the 

 Bay of Biscay," writes Sir Wyville Thomson, " gave 

 a very fair idea of the condition of the bottom of the 

 sea over an enormous area, as we know from many 

 observations which have now been made with the 

 various sounding instruments contrived to bring 

 up a sample of the bottom. On that occasion the 

 dredge brought up about r| cvvt. of calcareous mud. 

 There could be little doubt, from the appearance of 



