REPORT OH THE EORAMINIFERA. 
637 
embodiment of its typical characters. The test of this species takes the form of a some- 
what irregularly built cone with rounded apex, and is composed of a number of narrow 
segments arranged round a deep umbilical cavity. At the commencement of the shell 
the mode of growth is spiral, but subsequently the chambers are disposed in more or less 
distinct annuli, each individual segment having an orifice opening into the umbilical 
vestibule. The segments of the same annulus are not in close juxtaposition, but are 
separated by intervals of varying width ; these intervals are occupied by the segments of 
the following layer, and a more or less alternate arrangement of the segments of the 
successive annuli is thereby established. On the inferior face of the test the intervals 
appear in the form of symmetrically disposed depressions or radiating fissures. In adult 
specimens the umbilical recess is generally closed externally by a shelly flap, as seen in 
fig. 13, b. The chamber- walls, so far as visible on the superior aspect of the test, are 
conspicuously perforated, but on the inferior surface they are smooth, hyaline, and non- 
porous. Freshly collected shells are usually brown near the apex, the colour gradually 
disappearing towards the circumference. Fully grown specimens have a diameter of 
about -^g-th inch (O’ 7 mm.). 
A variety differing from the typical form in its comparatively depressed contour and 
the somewhat open arrangement of the segments on the inferior face, is represented 
by fig. 14, ct-d. In many localities this modification is more abundant than the type ; 
but whether its immediate relationship is with Cymbalopora poeyi or with Cymbalopora 
bulloides, is not very clear. 
Parker and Jones are probably correct in assigning the Roscdina squamosa of 
the “ Cuba ” memoir to the present species ; and that form is stated by d’Orbigny to be 
of parasitic habit, having been found plentifully growing attached to Fucus and Ulva 
lactuca, in the West Indies. 
Both Cymbalopora poeyi and the depressed variety are moderately common amongst 
the coral-sands of tropical and subtropical seas. Notes have been preserved of the occur- 
rence of one or other at six Stations in the North Atlantic (West Indies, Bermuda, 
Azores, &c.), the depths ranging from shallow water down to 450 fathoms ; at three in 
the South Atlantic, 350 to 675 fathoms; in the Red Sea, 15 to 20 fathoms; in shore- 
sands from Madagascar and the Mauritius ; in dredged sand from the Seychelle Islands, 
8 fathoms; at about twenty localities in the South Pacific, 3 to 610 fathoms; and at 
four in the North Pacific, 7 to 75 fathoms. 
Cymbalopora tabellceformis, n. sp. (PI. CII. figs. 15-18). 
Test depressed, peripheral outline rounded or oval ; superior face complanate or nearly 
so, inferior convex, but with an irregular umbilical cavity or recess ; peripheral edge obtuse 
or rounded. Composed of numerous segments, all of which are visible on the superior 
face ; segments inflated interiorly, sometimes arranged in more or less regular alternating 
(ZOOL. CHALL. EXP. — PART XXII. 1884.) Y 81 
