156 GREVILLE, ON.DIATOMACES. 
acquainted with their history. Something, nevertheless, it 
must be admitted, is gained by the publication of accurate 
figures; for even if they fail in some cases to establish 
species, they will at least assist to indicate the range of 
variation, a point in itself of no small importance. 
The prepared material of the Californian guano— the 
richest in diatomaceous forms which has come under my 
notice, and which has yielded, among many others, the 
species described in this paper—was kindly supplied to me 
by Mr. J. T. Norman, of Fountain Place, City Road, 
London 
Cocconets, KAr. 
C. regalis, n. sp., Grev.—Frustule orbicular ; striz monili- 
form, 5 in ‘001", occupying an elliptical space in diameter 
about a third of the entire valve, the rest of the valve filled 
with several rows of large granules concentric with both the 
sides and extremities ; diameter 0030". (Pl. VII, fig. 1.) 
In Californian guano. 
The most splendid species perhaps of the beautiful genus 
to which it belongs. The elliptical space occupied by the 
few coarse striz stops considerably short of the margin of 
the valve at each end, so as to admit of the rows of granules, 
which diminish in size as they approach the extremities, 
being continued round the whole valve. The granules are 
very large and prominent, and have much the effect as if 
they were the terminations of successive series of striz 
curving up from below to the surface. Some of the granules 
in the outer row are double and occasionally irregular. 
This fine species seems to be most nearly allied to C. 
Grevillii, a cosmopolitan Diatom, to which, in the structure 
of the upper valve, it bears a considerable general re- 
semblance. 
Avtacopiscus, Hhr. 
A. Oreganus (fig. 2), Harv. and Bail., ‘ Proceed. of Acad. 
Nat. Se. of Philadelphia,’ vol. vi. p. 430. 
At Puget’s Sound, Oregon, U.S., Exploring Expedition 
under Captain Wilkes. In Californian guano. 
Of this exquisite disc no figurehasbeen published. The single 
example I have found in Californian guano agrees minutely 
with specimens received from Professor Bailey in 1856, ex- 
cept in the number of radiating lines and nodules. Professor 
Bailey, in the specific character given in the work above 
quoted, fixes the number at thirteen. But of the two specimens 
