REPORT ON THE FORAMINIFERA. 
607 
round, but usually irregular, and sometimes entirely closed up by the inspissated gelati- 
nous sarcode, so as to be invisible” (Rec. For. Gt, Br., p. 2). His figure of the species, 
which corresponds accurately with that in d’Orbigny’s work, is copied in PI. LXXXI. fig. 25. 
The conspicuous characters, so far as they can be gathered from the majoritv of 
bottom specimens, are fairly indicated by these descriptions ; but it will be presently 
shown that it is more than doubtful whether, in the typical condition, the shell ever 
possesses an aperture, in the ordinary sense of the term ; and that the more or less regular 
openings which have been occasionally mistaken for the general orifice are probably in 
all cases the result of the accidental enlargement of ordinary pores. 
That the test does not always consist of a simple undivided chamber was first de- 
monstrated by Pourtales, w T ho in a brief note on the genera Orbulina and Globigerina 
announced that during the examination of “ large numbers of well-preserved specimens 
obtained from the bottom beneath the Gulf Stream,” he had “ found in nearly one half 
of the Orbulince examined, young Globigerince more or less developed and attached to 
the inside of the Orbulina by numerous very slender spiculse.” 1 Similar observations 
were made a few years later by Alcock upon shells found in littoral sands from the west 
coast of Ireland. 2 The same fact had been observed in living pelagic specimens by Krohn, 
as early as I860, 3 some time prior to the publication of Major Owen’s well-known 
memoir on Surface Foraminifera. 4 Carpenter, in his review of the observations made by 
Pourtales, states that “ after having carefully laid open, by the application of weak acid, 
the spheres of a considerable number of Orbulince ,” he had “ not met with a Globigerina 
in a single one.” 5 For myself, though I have never encountered the Globigerina- like 
internal shells in Orbulince from bottom-dredgings, to anything like the extent 
indicated by the American author, I have not unfrequently found them in a certain 
proportion of the specimens so obtained. 6 
1 Amer. Journ. Sci. and Arts, 1858, vol. xxvi. p. 96. 
2 Mem. Lit. and Phil. Soc. Manchester, 1865, ser. 3, vol. iii. p. 180. 
3 Fide Schultze, Wiegmann’s Archiv, 1860. — Transl., Ann. and Mag. Nat. Hist., ser. 3, vol. vii. p. 312. 
4 Journ. Linn. Soc. Lond., 1867, vol. ix., Zool., p. 149. 
5 Introd. Foram., p. 178. 
0 Since these sheets have been in the hands of the printer, I have received from the author, Herr G. Schacko of 
Berlin, an interesting and elaborate paper entitled “ Globigerinen Einschluss bei Orbulina” ( JViegmann’s Archiv, Jahrg. 
xlix. p. 428), which offers a reasonable explanation of these apparent discrepancies. Sliacko’s investigations, which refer 
to bottom-specimens, both recent and fossil, tend to show that the Globigerine shell is most conspicuous in compara- 
tively small Orbulince. He states that in a sphere of 0 - 3 mm. diameter, the Globigerine chambers occupied two-tliirds 
of the cavity of the test ; that one of 07 mm. diameter contained a Globigerina of 05 mm. diameter ; that in one of 
08 mm. diameter the Globigerine shell measured only 0 - 2 mm. ; whilst a specimen of still larger size, between 08 mm. 
and 0'9 mm., contained scarcely a recognisable trace of a Globigerine shell. Hence it would appear that in ordinary 
thick-walled bottom-specimens, the Globigerine shell has its maximum development in Orbulince of about 0 - 7 mm. 
diameter ; and that in spheres of more than 08 mm. it is either of insignificant size or entirely absent, in the latter case 
probably resorbed during the thickening of the outer wall. 
Broadly speaking, this accords with my own observations. I have never found a Globigerine shell in the interior of 
a very large bottom- Orbulina, and very rarely in one that could be called full-sized; but they are not uncommon in 
middle-sized and small specimens. 
