420 
THE VOYAGE OF H.M.S. CHALLENGER. 
median line. Aperture on the oblique face of the terminal chamber, surrounded by 
radiating lines. Dimensions, ^-th by -j^th inch (0'3 by 0*25 mm.). 
This is a very minute species, but interesting alike from the peculiarity of its contour 
and the apparent subdivision of the segments near the median line. A somewhat similar 
condition of the segments is seen in an elongate tapering variety of Bolivina figured by 
Ehrenberg (Mikrogeologie, pi. xxv. fig. 16) under the name “ Grammostomum poly theca ? ” 
Bolivina tenuis has only been met with at a single locality, — off Kandavu, Fiji Islands, 
255 fathoms. 
Bolivina nitida, n. sp. (PL LII. fig. 30, a.b.). 
Bolivina laevigata , Brady, 1881, Quart. Journ. Micr. Sci., vol. xxi., N. S., p. 57. 
Test elongate, thin, complanate, broadest at the centre, tapering and rounded towards 
the ends. Segments few in number, regularly Textularian in arrangement ; broad, 
flattened on both faces, and bordered both at sutures and periphery by a narrow band of 
clear shell-substance. Sutures even ; aperture large, irregularly oval, oblique. Length, 
^th inch (0'42 mm.). 
This species was originally described under the name Bolivina Icevigata, but as 
that term had been previously employed by Karrer for a different form, a fresh designa- 
tion has become needful. 
Found off East Moncoeur Island, Bass Strait, 38 fathoms ; and off Raine Island, Torres 
Strait, 155 fathoms ; rare in both localities. 
Bolivina tortuosa, H. B. Brady (PL LII. figs. 31-34). 
Bolivina tortuoca, Brady, 1881, Quart. Journ. Micr. Sci., vol. xxi., N. S., p. 57. 
Test elongate, tapering, broadest near the apertural end ; the margins bent obliquely 
towards the median line on either side, so as to give to the entire shell a twisted contour ; 
peripheral edge thin, sharp, lobulated. Segments numerous ; long and narrow ; the later 
ones projecting and rounded at the peripheral ends. Shell conspicuously perforated. 
Length, ^th inch (0’42 mm.) more or less. 
This species varies a good deal both as to size and contour. The figures 31, 32 and 
33, 34 represent average specimens from two different localities at which it occurs in con- 
siderable abundance ; the former from the Admiralty Islands, 1 7 fathoms, the latter from 
the Cape de Verde Islands, 1 1 fathoms. Near the Cape de Verde Islands it is also found in 
