25 



Rhizopods, PLATE 9 - 



Foraminiferce. 



Rotalia. One species alone is here figured in detail externally ; it Fl - * 

 is generally characteristic of all that numerous and widely-diffused 2000 fathoms 



J Lat.473'N. 



group. Long. 23 21' 



It will be here observed, that all the chambers, eleven in number, 

 are visible. (There are frequently thirteen chambers). 



The perforations for the foramina are very distinct, and the indenta- 

 tions through the tumuli easily seen. The newly or last formed 

 chamber is here transparent and colourless, while those near the first 

 formed chamber at the spire are coated with a light brown calcareous 

 deposit. All these forms were, by the high temperature of the Gulf 

 Stream, 42 to 71, in which they were found, more fully developed 

 than those a few miles north in Polar waters, being in many instances 

 double the size of them. 



(Polythalamvs.) 



(r'lvbtgerina. In this four-chambered form is seen the aperture or FIG. 2. 

 oritice which is carried from chamber to chamber, probably assisting 

 the Sarcode body to convey material to the inner chambers, or possibly 

 for some other useful purpose as yet unknown to naturalists. 



(Mon otha lamu s.) 



Orlulina. A simple calcareous spherical shell, found in great FIG. 3. 

 abundance, being a single cell or chamber, with its wall irregularly 

 perforated (well known and described). In none of these forms 

 (which were carefully examined) could any aperture be found ; pro- 

 bably the little inhabitant had enveloped and imprisoned itself, not 

 intending to add to its size or form by the multiplication of other 

 chambers, but living a perfect independent life ; and it is therefore 



