REPORT ON THE FORAMINIFERA. 
343 
Trochammina trullisscita is easily distinguished from any other species by its 
perfectly regular, nautiloid or Nonionine contour, the number of chambers in each whorl, 
the sigmoid sutural lines, and the polished brown exterior. In small specimens (fig. 14) 
the convolutions are somewhat less embracing than in those of larger size, the peripheral 
edge is rounded and more or less lobulated, and the test is of lighter hue. 
In general conformation, it is not unlike Cyclammina cancellata, but differs 
widely from that species in point of size and internal structure. The inner surface 
of the test is often punctate, as shown in fig. 16, and sometimes even exhibits a 
slightly raised reticulation ; but in every case these are mere superficial markings, and, 
though they may foreshadow in a rudimentary way the cancellated structure of some of the 
more complex types, they bear little actual resemblance to the tubulated growths that 
nearly obliterate the chamber-cavities of Cyclammina. 
The first examples of this beautiful little shell that came under my notice were in the 
Eev. A. M. Norman’s mountings from one of the “Valorous” dredgings in Davis Strait, 
depth 1750 fathoms, and this probably represents its northern geographical limit; 
its range in the southern hemisphere extends to Station 144, between the Cape of Good 
Hope and Kerguelen Island, about latitude 46° S. Its presence has been noted at 
twenty-five localities, pretty evenly scattered over the North and South Atlantic, the 
Southern Ocean, and North and South Pacific. Of these only five have depths of less than 
1500 fathoms, and fifteen are above 2000 fathoms. 
Trochammina r ingens, H. B. Brady (PI. XL. figs. 17, 18). 
Trochammina ringens, Brady, 1879, Quart. Journ. Micr. Sci., vol. xix., N. S., p. 57, pi. v. 
fig. 12, a. b. 
Test nautiloid, oblong, compressed, biconvex ; composed of few convolutions, of which 
the last entirely encloses those previously formed. Peripheral edge acute or slightly 
rounded, lobulate ; septal lines curved, somewhat excavated. Segments large, four or five 
in each convolution, embracing. Colour brown, surface usually polished. Aperture an 
arcuate slit overhung by a slight swelling or prominence ; situated on the face of the 
terminal chamber, near the margin of the previous convolution. Longer diameter, ^jth 
inch (1'25 mm.). 
Trochammina ringens is nearly allied to Trochammina trullissata, but the points of 
distinction are easily recognised. It has only about half the number of segments in each 
convolution, and the final whorl completely encloses the earlier ones, instead of leaving 
the penultimate coil partly exposed at the centre : the general contour of the test is 
biconvex, there is little or no depression in the umbilical region, and the terminal segment 
is conspicuously large. In the colour, texture, and external condition of the walls, the 
