MAJOE OWEN OSr THE STJEFACE-FATJlirA OE MID-OCEAIT. 149 



The outer sphere may be regarded as a wild-growing closing- 

 in chamber ; this form of growth is at times imitated by JPulvi- 

 nulina, the outer chambers of which species then take on the 

 same texture as is common to the outer chambers of Glohigerina 

 (Orbulina) universa. I am indebted to Mr. Parker for showing 

 me precisely analogous cases in the growth of Cymlalopora and 

 Discorbina ; but in each of these genera it appears to be much 

 rarer than in Glohigerina. 



I propose to make Orlulina a subgenus of Gloligerina. The 

 internal chambers are in form remarkably like those of Glohigerina, 

 and like them, also, they present themselves with varying surfaces, 

 some free from, while others are covered vpith, spines. The form 

 without internal chambers has been known under the name of 

 Orhnlina universa ; I propose now to call it Glohigerina (OrhuUna) 

 universa. The two forms containing the internal chambers may 

 be regarded as subspecies, and appropriately designated Glohi- 

 gerina (^Orhulina) continens, n. sp., and Glohigerina {Orhulind) 

 acerosa, n. sp., respectively, — the former being without, and the 

 latter having, spines on some of its internal chambers. These 

 spines, as well as those of G. hirsuta, are composed principally of 

 carbonate of lime. I have found that they dissolve in weak acid ; 

 and under Mr. Parker's treatment with boiling potassa they were 

 unaffected, which proves them to be not siliceous. 



These spines on G. hirsuta have been looked upon as ossifi- 

 cations of the pseudopodia ; but I find on examination that they 

 ' do not take their rise from the centre of the honeycombed de- 

 pressions of the surface in which the apertures are situated to 

 admit of the extrusion of the sarcode, but are continuations of 

 the material of the raised portions of the shell which surround the 

 hollows. Prom their delicate nature, most of them get broken 

 off in the nets ; when unbroken, their ends are pointed, not 

 very finely, but somewhat resembling the ends of Belemnites mu- 

 cronatus. The texture and formation of these outer chambers in 

 Glohigerina (Orhulina) universa vary considerably — from a thin, 

 fragile ball, to one in every respect equalling in thickness the 

 chambers of G. hulloides. 



The habits of Glohigerina and Fulvimdina, I have proved to 

 be' identical, inasmuch as both frequent the surface of the ocean, to 

 the possible exclusion of all other forms of the Poraminifera, and 

 have the power of rising to and descending from the surface. 



The one I find placed by Dr. Carpenter at the highest, and the 

 other at the lowest, end of their respective subfamilies. I think 



