THE VOYAGE OF H.M.S. CHALLENGER. 
*J62 
normal habitat by oceanic currents ; in this way it is possible after a careful examination 
of the species present in a Globigerina Ooze to tell approximately the latitude from 
which the deposit was collected.^ 
The pelagic Foraminifera are especially characteristic of all deep-sea deposits from 
average or moderate depths, or from 200 to 3000 fathoms, in some equatorial regions. 
Near shore and in polar regions their presenee is masked by the abundance of other 
materials, so that if present they do not as a rule make up a large part of the deposit, 
but 
Fio. 25 . — Ilastifierina pelagica, d’Orbigny. From the surface (^^). 
the major part of the deposits, or at all events of the carbonate of lime that is present. 
In all the greatest depths of the ocean in the tropics, and in the lesser depths of the 
ocean in extra-tropical regions, the shells of these pelagic Foraminifera are either not 
present in the deposits, or are met with only in a fragmentary condition ; like the Cocco- 
spheres, Rhabdo.^^pheres, Pteropods, and calcareous shells of other pelagic organisms, they 
have been wholly dissolved either in falling through the water or shortly after having 
reached the bottom.'^ 
' 8ec 1 .. 31. 
’ See Mtirray, I’roc. Hoy. Soc., vol. xxiv. p. 535, 187G; Proc. Hoy. Soc, Edin., vol. x. p. 509, 1880; Royal Institution 
lA-ctun-, Lon lon, March 10, 1888, j). 7; Narr. Chall. Exp., vol. i. pp. 923, 4; Murmy and Indne, Proc. Roy. Soc. Edin., 
vol. xvii. p. 8.3, 1889. 
