GrevillBj on New Diatoms. 
99 
LiRADlSCUS. 
Liradiscus ellipticus, n. sp.^ Grev.— -Disc elliptical^ oval^ or 
oblong, with the ends subacute ; sinuate reticulation very 
small. Length of disc about -0030". (Fig. 6.) 
Hab. Barbadoes deposit^ Cambridge estate ; in slides com- 
municated by C. Johnson, Esq. 
Very similar to L. ovalis, only with the ends always more 
or less acutCj and the reticulation comparatively minute. 
ASTEEOLAMPRA. 
Asterolampra eximiaj n. sp., Grev. — Large ; segments nu- 
merous^ more than one third of the radius in length, quad- 
rately cellulate, their inner margin very convex, and com- 
posed of elongated cellules; umbilicus irregularly cellulate. 
Diameter -0060''. (Fig. 10.) 
Hab. Barbadoes deposit, Cambridge estate; L. Hardman, 
Esq. 
A most beautiful species, quite distinct from those pre- 
viously described. The umbilicus is loosely and irregularly 
cellulate, and gives off, in the specimen before me, 22 umbi- 
lical lines. The segments are remarkable for the arched 
outline of their inner margin, which is composed of 6 linear 
elongated cellules, the 4 middle ones being more prominent 
than the 2 lateral ones. 
Btddulphia. 
Biddulphia ? decorata, n. sp., Grev. —Valve in front view 
rectangular, produced at the angles into short, thick, rounded 
processes, wholly filled with rounded cellules; median sur- 
face convex, with a single stratum of cellules, which in the 
front vievi^ appear to be vertically oblong ; the rest of the valve 
smooth, vdth one or two transverse rows of round cellules. 
Length -0026". (Fig. 7.) 
Hab. Barbadoes deposit, Cambridge estate ; in slides com- 
municated by C. Johnson,. Esq. 
I have only seen two specimens of this diatom, the genus 
of which must be considered doubtful. The median surface 
is curious; the upper half of the oblong cellules projecting 
above the line, which would render the surface papillose. 
