646 
THE VOYAGE OF H.M.S. CHALLENGER. 
Discorbina isabelleana, d’Orbigny, sp. (PL LXXXVIII. fig. 1 , a.b.c.). 
Rosalind isabelleana, d’Orbigny, 1839, Foram. Am4r. Merid., p. 43, pi. vi. figs. 10-12. 
Discorbina isabelleana, Parker and Jones, 1872, Quart. Journ. Geol. Soc., vol. xxviii. p. 115. 
A minute thin-shellecl variety also belonging to the “ rosacea ” group. 
Dredged off Tahiti, 620 fathoms ; found by d’Orbigny in sands from the Falkland 
Islands. 
Discorbina eximia, Hantken (PI. LXXXVIII. fig. 9, a.b.). 
Discorbina eximia, Hantken, 1875, Mittheil. Jalirb. d. k. ung. geol. Anstalt, vol. iv. p. 76, pi. xv. 
fig. 8. 
,, elegans, Id. Ibid. p. 76, pi. ix. fig. 3, a.b.c. 
It appears to me scarcely possible to separate the Discorbina eximia and Discorbina 
elegans of von Hantken, and as the latter term is already in use for another modification 
of the genus, 1 the former may be adopted for the present variety. 
Occurs at Station 185, off Paine Island, Torres Strait, 155 fathoms. 
Von Hantken’s specimens were from the later Clavulina-szaboi formation of Hungary. 
Discorbina concinna, n. sp. (PI. XC. figs. 7, 8). 
Test free ; outline circular, superior face convex, inferior somewhat concave, peripheral 
edge angular; composed of somewhat more than two convolutions, of which the latest 
consists of from three to four segments. Earlier segments, in their superior aspect, short 
and radial later segments long and crescentiform ; on the inferior side, the final segment 
occupying nearly half the entire surface, umbilical flaps distinct but not greatly developed. 
Walls very thin and conspicuously perforated ; sutures marked by fine lines, neither 
depressed nor limbate externally. Diameter, inch (0'25 mm.). 
It is possible that this little organism may be only the immature or arrested stage of 
some better-known species ; but, though common in several localities, I have been unable 
to associate it with any of the larger modifications of the genus. 
It inhabits tropical seas, occurring at two points off Tahiti, depth 420 fathoms and 
620 fathoms; and at two off Kandavu, 255 fathoms and 610 fathoms respectively; also 
off Amboyna, 15 to 20 fathoms; off the Admiralty Islands, 16 to 25 fathoms; and off 
the Philippine Islands, 95 fathoms. 
1 Discorbina elegans, d’Orbigny, sp. ( Anomalina elegans, Ann. Sci. Nat., 1826, vol. vii. p. 282, No. 4 ; — Module, No. 42). 
