632 
THE VOYAGE OF H.M.S. CHALLENGER. 
generally more prominent on one side of the test than on the other. Diameter, g^th to 
•^th inch (0‘5 to 1 mm.). 
This form is closely allied to the Spirillina margaritifera of Williamson. It may be 
distinguished by the somewhat embracing contour of the tube, and the nearly complanate 
sutures, as well as by the exostoses, which, instead of being few in number and arranged 
in a single row, are scattered in profusion over the whole surface of the test. 
The figured specimens are all from Balfour Bay, Kerguelen Island, 20 to 50 fathoms. 
The species occurs also in Christmas Harbour, Kerguelen, 120 fathoms ; in the Sarmiento 
Channel, west coast of Patagonia, 400 fathoms ; off Kandavu, 210 fathoms ; off Honolulu, 
40 fathoms ; and on the shores of Madagascar. Small specimens have also been taken 
at one or two points on the British coast. 
Spirillina limbata, H. B. Brady (PL LXXXV. figs. 18-21). 
Spirillina limbata, Brady, 1879, Quart. Jouru. Micr. Sci., vol. xix., N. S., p. 278, pi. viii. 
fig. 26, a.b. 
Test planospiral, thin, equilateral, discoidal ; lateral faces flat or only slightly concave ; 
peripheral edge square. Spiral sutural line marked externally by a raised band of shelly 
deposit; surface otherwise smooth. Diameter, -g^th to F^th inch (0‘42 to 0‘84 mm.). 
In Spirillina limbata the shell-wall is thicker and the perforations are less conspicu- 
ous than in many other varieties of the genus ; but the really distinctive characters are 
the sutural limbation and the square periphery. It is isomorphous with Cornuspira 
crassisepta in the porcellanous group. 
The distribution-list of the species embraces altogether thirteen localities, which are 
apportioned as follows one in the North Atlantic, one in the Mediterranean, three in 
the South Atlantic, one in the Southern Ocean, six in the South Pacific, and one in the 
North Pacific. One of the South Atlantic Stations has a depth of 1425 fathoms, but 
with this exception the bathymetrical range is from 6 to 675 fathoms. 
Spirillina limbata, var. denticulata, nov. (PI. LXXXV. fig. 1.7). 
External form and general characters of the test resembling those of Spirillina lim- 
bata ; the raised spiral band covering the sutural line furnished with buttress-like teeth, 
set at regular intervals along its inner margin. 
This rather ornate variety occurs off East Moncoeur Island, Bass Strait, at a depth of 
38 fathoms ; and in company with the simply limbate form, off Baine Island, Torres 
Strait, 155 fathoms, and in Nares Harbour, Admiralty Islands, 17 fathoms. 
