EEPOET ON THE FOEAMINIFEEA. 
141 
Una sphcera, but tliey may generally be distinguished by the ordinary Milioline aperture, 
and by the extent to which the penultimate chamber is exposed. Probably the form 
named by Reuss Biloculina globulus (loc. cit.) is one of these ; it differs considerably 
from that species as originally figured by Bornemann. 
Specimens of Biloculina irregularis have been obtained from Challenger material 
dredged off Palma, Canaries, 1125 fathoms; off Sombrero Island, 450 fathoms; south of 
Pernambuco, 350 fathoms ; in mid-ocean, South Atlantic, 1415 fathoms; off Fiji, 610 
fathoms ; off Tahiti, 620 fathoms ; and north of Papua, 1070 fathoms. 
The localities of the fossil (Tertiary) forms figured by Reuss, above referred to, are 
respectively the Septaria-clay of Hermsdorf, near Berlin, and the Salt-beds of Wieliczka 
in Galicia. 
Biloculina sphcera, d’Orbigny (PI. II. fig. 4, a.b.). 
Biloculina splicera, d’Orbigny, 1839, Foram. Am4r. Merit!., p. 66, pi. viiL figs. 13-16. 
„ globulus, Bornemann, 1855, Zeitsehr. d. deutsch. geol. Gesell., vol. vii. p. 349, pi. xix. 
fig. 3, a, b. 
„ sphcera, Brady, 1864, Trans. Linn. Soc. Lond.,vol. xxiv. p. 466, pi. xlviii. fig. 1 ,a, b. 
„ globulus, Eeuss, 1870, Sitzungsb. d. k. Ak. AViss. AYien, vol. lxii. p. 464; — 
Scbliclit, 1870, Foram. Pietzpubl, pi. xxxv. figs. 30-32. 
There are few Foraminifera more easily identified than well-grown specimens of 
Biloculina sphcera. The globular contour first attracts attention, then the investing char- 
acter of the final chamber, which encloses the whole of that preceding it except a little 
circular patch just below the aperture, and lastly the aperture itself, which often presents 
somewhat anomalous features. 
D’Orbigny in the “ South America ” monograph, loc. cit., suggests rather than delineates 
the orifice, and the figure referred to in my own paper on Shetland Foraminifera was taken 
from a specimen of the particular form which is common in the com- 
paratively shallow water of the Scottish coast, and shows no charac- 
teristic deviation from the ordinary Biloculine type. The shell 
figured in PL II. fig. 4 is a fair representative of the deep-water 
examples of the species ; but the bordered V -shaped slit, which is 
perhaps its most conspicuous feature, is only one out of many forms 
the aperture assumes, and it is quite as common to find in deep-sea 
specimens a labyrinthic or dendritic orifice such as that portrayed 
in the annexed woodcut (fig. 1). 
That the shell figured by Bornemann, loc. cit., under the name 
Boliculina globulus, as well as those above referred to in the plates of von Sclilicht’s 
memoir, belong to the present species, hardly admits of doubt. Bornemann’s name, 
however, is used by Reuss, in his notice of the Foraminifera of the Septaria-clay of 
(ZOOL. CHALL. EXP. — PART XXII. — 1883.) Y 19 
Fig. 1. — Labyrinthic 
aperture of Bilocu- 
lina sphcera. Mag- 
nified 40 diam. 
