592 
THE VOYAGE OF H.M.S'. CHALLENGER. 
Scheme of the Genus GLOBIGEEINA. 
A. Test Rotaliform, chambers' opening individually into an inferior umbilical vestibule. 
1. Segments globular, about seven in number, four in the outer whorl, 
2. Three segments in the outer whorl, relatively very large, 
3. Shell turbinoid, orbicular, somewhat compressed ; segments 
numerous, inflated, five or six in 'the outer whorl, 
4. Shell much compressed, outspread ; with about three distinct 
convolutions ; segments five or more in the outer whorl, 
5. Shell biconvex, much compressed ; periphery thin or subcarinate ; 
segments numerous, marginate, .... 
6. Shell compressed or complanate ; periphery thick, square, or bicari- 
nate ; segments numerous, arranged in about three whorls; 
sutures limbate, ...... 
7. Shell trochoid ; early segments small and regular, later segments, 
especially the final one, much elongated, and spreading radially, 
Gl. bulloides, d’Orb. 
„ „ var. triloba, Reuss. 
Gl. dubia, Egger. 
Gl. cretacea, d’Orb. 
Gl. marginata , Reuss, sp. 
Gl. linnoeana, d’Orb., sp. 
Gl. digitata, Brady. 
B. Test Rotaliform, external aperture a single arched opening at the inferior umbilical margin 
of the final segment. 
8. Shell small, subglobular, somewhat compressed : consisting of two 
convolutions, the outermost composed of four segments ; seg- 
mentation obscure externally, .... Gl. pachyderma, Ehrenb., sp. 
9. Shell rounded, both faces convex; consisting of about three con- 
volutions, the outermost having five segments ; later segments 
inflated ; aperture semicircular, comparatively small, . . Gl. dutertrei, d’Orb. 
10. Superior face nearly flat, inferior highly convex, peripheral edge 
rounded ; four segments in the outer whorl ; aperture large 
and gaping, . . . . . Gl. inflata, d’Orb. 
Test Rotaliform ; aperture a single arched orifice on the inferior face, and two, three, or 
more rounded openings in the sutural depressions of the superior face. 
11. Shell forming a regular, more or less elevated, trochoid spire; 
three segments in the final convolution ; colour pink, 
12. Shell nearly spherical, compact; the three segments of the final 
whorl large and inflated, forming a convex base, 
13. Shell oblong, compressed; segments few, four in the outer eon- 
volution ; ultimate segment, and sometimes the penultimate, 
elongated radially and more or less pointed, 
1 4. Shell oblong, ovate ; the outer whorl consisting of four segments, 
two large and oblong, side by side, two small and rounded 
placed one at each end, 
Gl. rubra, d’Orb. 
Gl. conglobata, Brady. 
Gl. sacmlifera, Brady. 
Gl. kelicina, d’Orb. 
D. Test planospiral, bilaterally symmetrical, aperture on the median line, 
15. Test e volute, loosely coiled, aperture symmetrically placed at the 
inner margin of each segment, ..... Gl. cequilateralis, Brady. 
With reference to Globigerina digitata, it may be remarked that large examples have 
a tendency to assume the planospiral mode of growth, the outer convolution almost enclos- 
