18 ANNIVERSARY ADDRESS. 



Five distinct conditions of the sea bottom were ascertained, 

 without reckoning as one the detritus of shallow soundings near 

 land. 



All the organisms at the bottom in certain depths were dead, 

 and the Olobigerina ooze consisted of but little else. It appears 

 that the living Foraminifera float on the surface, or at some 

 intermediate depth, but subside to the bottom after death, and 

 the Professor has satisfied himself of that fact. From all seas, 

 from the Equator to the Polar ice, the tow net contains GJobi- 

 gerince, but they are smaller as the distance increases from the 

 equator. The living Globigerince differ from the dead inasmuch 

 as the former are ornamented by flexible calcareous spines, 

 springing from the deep hexagonal borders of the pores. " The 

 spines radiate symmetrically from the direction of the centre of 

 each chamber of the shell, and the sheaves of long transparent 

 needles crossing each other in different directions have a very 

 beautiful effect." The smaller chambers are filled with an orange 

 yellow sarcode, or a portion of it adhering to one side. No 

 structure was detected in that sarcode. The spines are so delicate 

 that they break off with the slightest touch, and are never found 

 at the bottom, even when it is shallow. Orbulina universa is 

 another of the Foraminifera which is sometimes also found with 

 nearly empty chambers. It is supposed by some writers to be 

 the young of Globigerina. The two genera, however, do not 

 always occur together on the surface, but both are more fully 

 developed and abundant in the warmer seas. South of Kerguelen 

 Island, neither Orbulina nor Pulvinulina (which has two species) 

 was detected. Other minute organisms occur with the former^ 

 In the intertropical regions the bulk of the ooze is made up of 

 shells and fragments of shells of the above Foraminifera, yet in 

 some cases at least 20 per cent, of a fine granular calcareous 

 matter cements and fills the shells. This, under the microscope, 

 comes out as " coccoliths" and " rhabdoliths." 



These last-named are the armatures of certain spherical bodies — 

 cocco spheres and rhabdo spheres — which are surface inhabitants 

 of the warmer seas, and are considered to belong to the Algce. They 



