REPOET ON THE FORAMINIFERA. 
751 
biconvex lens, the thickness of which at the middle is equal to one-third of its diameter 
( Cycloclypeus neglectus, Martin); whilst in other instances, like the little species about to 
be described, the lateral deposit is almost confined to a small area near the centre. 
Structurally the lateral plates are composed of a succession of superimposed lamellae, 
and, except the columns terminating in the external tubercles, which are solid, they are 
traversed vertically by fine, closely set, parallel tubuli. 
The septal walls of the chambers of the central plane are always double, and the 
entire shelly skeleton is furnished with a complicated system of canals which need not 
here be minutely described. 
Our knowledge of the distribution of the genus as a recent type of Foraminifera is 
limited to one or two localities in the Eastern Archipelago. Fossil representatives have 
been obtained by Carter from the early Tertiary limestones of the south-east coast of 
Arabia, and by Martin from rocks of similar age in Java. 
Cycloclypeus guembelianus, H. B. Brady (PL CXI. fig. 8, a.b.). 
Cycloclypeus guembelianus , Brady, 1881, Quart. Journ. Micr. Sci., vol. xxi., N. S., p. 66. 
Test discoidal, outline nearly circular ; biconvex or subumbonate ; the central portion 
of both faces considerably thickened, the outer zones gradually thinning towards the 
periphery, which presents a sharp edge ; composed of comparatively few annuli. 
Segments approximately square ; when otherwise, the radial diameter usually shorter 
than the peripheral. Both the annular and radial sutures marked externally by slightly 
raised lines, the surface of the test being otherwise smooth. Diameter, ^th inch 
(1’5 mm.). 
Two or three tolerably complete specimens of this interesting form have been met 
with. Notwithstanding their minute dimensions in comparison with the only other 
recent species hitherto obtained, they are to all appearance fully grown. Apart from the 
size, their distinctive features appear to be the shape of the chambers, and the relatively 
slight development of the lateral shelly plates. 
Carpenter describes the “ typical form of the chambers ” as “ a parallelogram whose 
sides are to each other as 1^ to 1, or as 2 or even 3 to 1, the longest side lying in the 
direction of the radius of the disk.” The chambers of the present variety are nearly 
equilateral, when otherwise, the radial diameter is the shorter of the two. The lateral 
layers of shell-substance are so little developed that the septation is visible nearly to the 
centre of the test, and there is an entire absence of the superficial tubercles wdiich form a 
common feature of the larger species. 
I have suggested in a previous paper 1 that the type specimens of Cycloclypeus in the 
1 Quart. Journ. Micr. Sci, vol. xxi., N. S., p. 67. 
