ROPER, ON BRITISH MARINE DIATOMACE. 21 
short intervals by rays, extending from a band of submarginal 
spines almost to the centre, where there occur from three to 
eight irregularly shaped larger cellules.” Cellules 10 to 26 
in 001”; diameter 0025” to :018”. 
I figure a small specimen as the structure is precisely 
similar, and cellules vary little in size from those in the 
largest valves, those with 10 to 20 in :001 being rather rare, 
and I have only found them of this size in the specimens 
from the Humber. 
Coscinodiscus labyrinthus, un. s.—Cellules hexagonal, minute, 
arranged in quincunx in large irregular hexagonal spaces, 
divided by lines of confluent cellules or dots; valves not 
spinous at the margin, but with a ring of minute submar- 
ginal papille. Diameter :0018" to 00247” ; diameter of hexa- 
gonal spaces ‘00027" to -00038”; cellules 15 in ‘001" (fig. 2 a 
and 8). 
Marine. Caldy, Pembrokeshire, Rev. J. Guillemard. 
I have only met with four specimens of this peculiar species 
in the slides I have examined from the Caldy gathering, but 
the arrangement of the cellules is so different from any yet 
figured, that it may fairly be entitled to rank as a new 
species. It has somewhat the aspect, under a low power, of 
a finely marked specimen of C. eccentricus, but differs in the 
absence of the spmous margin, and in the peculiar arrange- 
ment of the cellules, which have somewhat the appearance of 
whorls or coils of dots, as shown in fig. 2 5, the surface of 
the valve being thus divided into large and irregularly shaped 
hexagonal spaces, without any clearly defined margin. C. 
eccentricus occurs abundantly in this gathermg; but neither 
in this nor in any other locality in which I have met with it, 
has there been any tendency to a similar arrangement of the 
cellular markings. 
Coscinodiscus (?) stellaris, n. s.—Cellular markings very 
minute, with five or six larger cells or dots arranged as a star, 
in the centre; surface slightly convex; margin not spinous ’ 
colour of dry valve, brown. Diameter -00252” (fig. 3). 
Marine. Caldy, Pembrokeshire, Rev. J. Guillemard. 
The detached frustules and single valves of this species are 
abundant in the Caldy gathermg. The markings on the 
surface of the disk are exceedingly fine, and have much the 
appearance of the transverse striz on Pleurosigma angulatum, 
even when seen with an 4-objective and oblique light. The 
star-like arrangement of cells or dots is found in the centre 
of both valves, and is readily distinguished with a magnifying 
power of 200 diameters. The strize are so inconspicuous, and 
