634 Messrs. e. heron-allen and a. earland oiJ 
is moderately common iu the material, as it is, indeed, in sliallou-water 
gatherings from most tropical and temperate seas. Liebus and Schubert's 
variety, D. tahernacularis, var. levis (Jahrb. k.-k. geol. Reichsanst. 1902, 
vol. Hi. p. 301, fig. 5), lias many points o£ resemblance, but differs in the 
absence of the characteristic radial beading which decorates the base of 
I), lawtei, as it does the base of T). tahernacularis. 
165. DiscoEBiNA PYEAMI0ALIS, sp. nov. (PI. 37. figs. 56-61.) 
Test free, shaped like a four-sided pyramid with slightly excavated sides, 
and salient angles, consisting of 3-5 convolutions, each of four chambers, the 
widest portion of each chamber being at the angle, and the sutural divisions 
running down the middle of each side. Shell-wall thick ; the base excavate, 
studded with beads, arranged radially, with the aperture of the final chamber 
in the umbilical recess. In all the specimens examined in balsam the 
primordial chamber is large and spherical, occupying as much as a quarter 
of the pointed apex of the pyramid. 
Several " twinned " pairs occur. The specimens are usually about the 
same size. There is a considerable i-ange botli in size and height of the free 
individuals ; in fact, there appear to be two fairly distinctive forms, one small 
and more or less regularly pyramidal (/'. e., the height being roughly equal to 
the diameter of the base), the other with a height double that diameter. 
These may represent the megalo- and raicrospheric stages of the organism. 
Among other variations noticeable are (1) a single three-sided specimen, 
(2) several specimens in which the angular edges of the pyramid are curving 
lines, so that, when viewed from the top, a spiral structure is suggested. 
The shell is thick and free from surface ornamentation. 
This species is evidently closely allied to Millett's D. corrugata (M, 1898, 
etc., FM. 1903, p. 700, pi. 7. fig. 5). We have good examples of this, from the 
Arakan coast of Burraah. Millett's original types, which are in our possession, 
bear, in his handwriting, as locality " Sagami Bay, Japan." Millett's form 
lias fi.ve salient angles and a much less polished exterior than .D. pt/rcmiidalis. 
We have typical specimens of D. pyramidqlis from Suva, Fiji Is. (12 fms., 
very rare), and we have noted its occurrence at 'Challenger' Station 185, 
" Raine Id." (155 fms., also very rare), so that we may assume that the 
form is widely distributed in the tropical Pacific. It is of constant occur- 
rence in a series of shore-sands which we possess from St. Vincent's Gulf 
and Spencer Gulf (S. Australia), and it also occurs in two shore-sands from 
W. Australia (Fremantle and Rottnest Island). The lack of suitable 
material from the remaining shores of Australia renders the records incom- 
plete, but it appears highly probable that the species will be found to be a 
typical form in Australian shore-gatherings. 
Size. Basal diameter at edges •08-"16 mm. (small type) to '28 mm. (large 
ty[ie). Heiglit •05-"21 mm. (small type) to '35 mm. (large type). 
