470 Mr. H. J. Carter on a new Species of Foraminifera. 



Of these twenty Greenland and Grinnell-Land Echino- 

 derms, 



Foiu'teen are common to America and Europe ; 



Three are known as American and not European ; 



Two are known as European and not American ; 



One now first recorded from Grinnell Land only. 



Analysis similarly shows that fourteen oat of the twenty 

 are Grinnell-Landic. And of these, 



Eleven are common to America and Europe ; 



Two are known as European and not American ; 



One from Grinnell Land only. 



Reasoning from present information, the writers are of 

 opinion that the character of the Echinifauna under considera- 

 tion is the effect of local modification acting upon a great polar 

 distribution rather than of intercontinental emigration simply. 



LVIII. — Description of anew Species of Foraminifera (Rotalia 

 spiculotesta). By H. J. Carter, F.R.S. &c. 



* [Plate XVI.] 



Ever since my description and illustrations of the structure 

 of the shell of Operculina arabica were published (' Annals/ 

 1852, vol. X. p. 161, pi. iv.), I have felt certain that the spicu- 

 liform bodies therein described and figured were integral parts 

 of the test, and not occasioned by any particular arrangement 

 of its canal-system as stated by Dr. Carpenter, any more than 

 the bricks of a house are dependent for their form on the 

 position of the gas- and water-pipes. How far I was justified 

 in making this assertion may be learnt from the following 

 description of this new species of Foraminifera. 



Rotalia spiculotesta, n. sp. (PL XVI. figs. 1-3.) 



Parasitic, sessile, flat, subcircular, with in-egular margin ; 

 colour dark brown in the centre, where the chambers are still 

 filled with dried sarcode, becoming snow-white towards the 

 margin, where they are more or less emptied by its contraction. 

 Chambers commencing from a slightly raised, central, spheri- 

 cal, embryonal or primary cell, in regular spiral succession, 

 soon becoming most irregular both in size and shape, when 

 the spire can be no longer traced, as they descend outwards to 

 a margin so irregularly undulating as to present in some parts 

 narrow conical processes, while in others they are wide and 

 round. Aperture not seen, but probably inferior, as none 

 could be observed above. Test entirely composed of round, 



