246 O’MEARA, ON NEW FORMS OF DIATOMACES. 
Stauroneis rhombica, n. sp., O’M., fig. 3, x 600.—Length of 
the valve 0017, greatest breadth ‘0012; rhomboido-elliptical, 
with narrow lanceolate apices. Strie very fine, punctate, 
and parallel; stauros narrow, the transverse limb of uniform 
breadth, and equal in length to half the breadth of the 
valve. 
Stauroneis costata, n.sp., O’M., fig. 4, x 600.—Length 
of the valve ‘0021, breadth 0009. Narrow elliptical, rounded 
at the ends. Stri distinctly costate, and gently waved, the 
transverse limb of the stauros short, and of equal breadth 
throughout. 
Cocconeis clavigera, n. sp., O’M., fig. 5, x 600.—Valve 
broadly elliptical ; length 0014, breadth 0011. Strize costate ; 
the coste radiate, club-shaped, very fine at the median line, 
and gradually expanding towards the margin, not reaching 
the margin. 
Cocconeis Wrightii, n. sp., O’M., fig. 6, x 800.—Valve 
broadly elliptical; length -0017, breadth 0012. A narrow 
border is closely studded with slightly. elongated cellules. 
The central nodule is expanded in the form of two crescents, 
touching at their convex centres, aud radiating towards 
the apices. Strie moniliform, arranged in curves nearly 
parallel with the limbs of the crescent-like expansions of the 
central nodule. 
Cocconeis Portii, n. sp., O’M., fig. 7, x 800.—Valve very 
minute ; length -0009, breadth -0007 ; broadly elliptical, with 
a narrow border. Strie radiate, punctate. The puncta very 
minute at the median line, and gradually enlarging towards 
the outer margin. The median line broad. 
Rhaphoneis liburnica, var., fig. 8, x 600.—Valve broadly 
elliptical ; length -0018. Striz radiate; the cellules, which 
are not more than six in the longest stria, appear slightly 
projecting above the surface of the valve, are quadrangular 
at the base, narrower and rounded towards the top; raphe 
narrow elliptical; valve without border; margin striated. 
At first I was disposed to regard this form as a distinct 
species, but on consideration preferred to refer it to Raphoneis 
hburnica, Grunow. The specific description of R. liburnica 
given by that author agrees with the general characters of 
this form, but the hispid appearance of the cellules and 
their quadrangular figure at the base entitle it to be regarded 
as a variety. 
Rhaphoneis suborbicalaris, n. sp., O'M., fig. 9, x 600.— 
Valve nearly orbicular ; length ‘0022, breadth ‘0019 ; divided 
into compartments by short costz, eight on one side, nine on 
the other, alternately disposed. The spaces between the 
