604 
THE VOYAGE OE H.M.S. CHALLENGER. 
Globigerina sacculifera, H. B. Brady (Pl. LXXX. figs. 114-17 ; PL LXXXII. fig. 4). 
♦ 
Globigerina lielicina, Carpenter, 1862, Introd. Eoram., pl. xii. fig. 1L 
„ sacculifera, Brady, 1877, Geol. Mag., Dec. II., vol. iv. P- 535. 
„ „ Id. 1879, Quart. Journ. Micr. Sci., vol. xfix., N. S., p. 73. 
Test oblong, compressed, Rotaliform ; segments few, usually five t o seven in number, 
of which four generally compose the final convolution ; earlier chambers small and sub- 
globular ; the ultimate segment, and sometimes also the penultimate, elongated radially 
and more or less pointed at the peripheral extremity. Aperture variable; consisting of 
a single large opening at the inferior umbilical margin of the terminal segment, and one 
or sometimes several rounded orifices in the sutural depressions of the superior face. 
Pelagic specimens spinous externally. Longer diameter ^g-th inch (1 mm.) more or less. 
Globigerina sacculifera is an exceedingly well-marked variety, originally described 
in a note on the Foraminifera of a white friable limestone from New Britain (Geol. Mag., 
loc. cit.). It belongs to the “rubra” section of the genus, and is characterised by its 
large outspread test, of which the terminal chamber or chambers are pouch-shaped or 
pointed. The apertures on the superior surface are numerous and that of th e final seg- 
ment is sometimes directly over the inferior orifice, making a passage, as it >vere, right 
through the shell. The test is thick and strongly built, resembling that of Globigerina 
conglobata. The tubulation of the walls is likewise coarse and conspicuous, t he indivi- 
dual pores frequently showing a diameter of 2 s mo oth inch (O'Ol mm.) or mor-5. In rare 
instances, notably in specimens from the West Indies (Station 24), the shells exhibit a 
certain amount of pink coloration. The pelagic examples collected on the Challenger 
Expedition were mostly in the young condition and spinous externally. 
The general contour of the shell is not unlike that of the smaller specimens of 
Globigerina digitata, from which species, however, it may always be distinguished by the 
apertures on the superior face, and by the smaller number of segments ; anij generally 
also by its much larger dimensions. 
The geographical distribution of Globigerina sacculifera is almost identical V with that 
of its near ally Globigerina conglobata, and includes an area stretching from nbout 40 
degrees north to 35 degrees south of the equator. Like the latter species fit is most 
abundant in the South Pacific and least common in the North Pacific. 
Some uncertainty exists as to its occurrence in the fossil state. The specimens first 
described were from a piece of calcareous rock supposed to be Chalk, but which on exami- 
nation revealed a microzoic fauna exactly analogous to the Globigerina ooze ofi the 
tropical region of the Pacific, just south of the equator. It appears probable, therefore, 
that the rock in question was a compact fragment from a recent sea-bottom which! had 
been disturbed by volcanic or other agency. 
