REPORT ON THE FORAMINIFERA. 
647 
Discorbina orbicularis, Terquem, sp. (PI. LXXXYIII. figs. 4-8). 
Rosalinci orbicularis, Terquem, 1876, Anim. sur la Plage tie Dunkerque, p. 75, pi. ix. fig. 4, a.b. 
Discorbis orbicularis, Bertlrelin, 1878, Foram. de Borgneuf et Pornicket, p. 39, No. 63. 
Discorbina rosacea , Terrigi, 1880, Atti dell’ Accad. Pontif., ann. xxxiii. p. 200, pi. iii. figs. 54, 
55. 
„ minutissima, Seguenza, 1880, Atti B. Accad. dei Lincei, ser. 3, vol. vi. p. 149 pi. 
xiy. fig. 1 , 1 , a.b. 
The minute scale-like Foraminifer to which Terquem has given the name Rosalina 
orbicularis presents extremely variable characters. Typically the test is much depressed 
and its peripheral outline nearly circular ; the superior face is convex or subconical, the 
inferior plane or concave, and the peripheral edge thin and sharp. In their superior 
aspect the segments are long, curved, and overlapping ; those of the later convolutions 
extending to nearly half the circumference of the shell. The sutures are generally 
marked by fine lines, but occasionally are more or less limbate externally. On the 
inferior face only three, or at most four, segments are visible, the last occupying 
nearly half the entire area, the umbilical flaps being tolerably well marked. The 
walls are nearly always delicately thin and conspicuously perforated. The shell 
occasionally attains a diameter of -g^th inch (0'84 mm.), but more frequently does not 
much exceed half that size. 
Terquem figures fossil specimens of the same form, but with the astral flaps more 
prominently developed, as Asterigerina rhodiensis (Mem. Soc. geol. France, ser. 3, vol. i., 
Mem. III. p. 31, pi. iii. figs. 1-4). 
Discorbina orbicularis is best known as a coral-reef species, though by no means 
confined to such localities. It is plentiful in shallow water amongst the islands of the 
Pacific, and also amongst the West Indies. Rare specimens have been found as far north 
as the Atlantic shores of France (Terquem, Berthelin), and the east coast of Ireland 
(Balk will) ; and as far south as the southern coast of Australia. Its ascertained range of 
depth is from the littoral zone to 435 fathoms. 
As a fossil it occurs in the Miocene of Southern Italy (Seguenza), and in the Upper 
Pliocene sands of Rome (Terrigi). 
Discorbina patelliformis, n. sp. (PI. LXXXYIII. fig. 3, a.b.c.; PL LXXXIX. fig. 1, 
a.b.c.). 
Test free ; superior side conical, inferior flat, peripheral edge acute : in the adult 
state composed of fully three convolutions, of which the outermost has from five to seven 
segments ; segments in their superior aspect long and narrow, the sutures and margin 
marked by broad lines of clear shell- substance, but not limbate externally. Superior 
surface smooth ; inferior ornamented either with faint riblets radiating from the umbilicus 
