516 PROFESSOR GREGORY ON 
margin. Valves transversely striated. Strize about 24 in 0-001’, conspicuous. 
The portion of the valve outside of the curve line seems to be in a plane different 
from that of the inner portions, and the strize on the latter are radiate. 
This well-marked and conspicuous species, remarkable for the position of the 
central nodules, is by no means rare in one of the Loch Fine dredgings, in which, 
except this form, Campylodiscus angularis, and C. Ralfsii, but few forms are found. 
It occurs more sparingly in some of the other dredgings. 
79. Amphora robusta, n. sp. Pl. XIII. figs. 79, 79 6, and 79 c. Form of frustule 
a broad oval with subtruncate extremities. Length from 0-0033’ to 0-0048", occa- 
sionally even as much as 0-006. Breadth from 0-0018’ to 0:0024". Valves arcuate, 
with the ends more or less obtuse; ventral margin straight or slightly concave. 
Inner curve lines very sharp and strong, rise from the inner angles, pass outwards, 
without reaching the outer margin, and bend suddenly inwards to the central 
nodules, which are within the ventral margin, by one-fifth of the width of the valve. 
In some specimens, or perhaps in a certain focus, the points where the two curve 
lines meet in the middle is on the inner side of a straight line, apparently forming 
the inner margin of the valve, so that a small blank triangular space is included 
between that straight line and the ends of the two curve lines. This produces a 
very peculiar aspect. Frustule thick, marked with strong strive, which on the 
compartments outside the curve lines are transverse, but on the inner terminal 
compartments are somewhat radiate. Strize subdistant, moniliform, about 16 in 
0-001". Figs. 79 6, and 79 c, represent two valves, in one of which the curve lines 
are seen, while it is evident that the inner compartments are in a different plane 
from the outer one. The other shows the entire valve viewed in a different focus, 
in which the strize appear all in one plane. 
This fine form, conspicuous for its size and the stoutness of its aspect, is not 
rare in the Loch Fine dredging mentioned under A. turgida, and occurs also in 
Lamlash Bay. 
80. Amphora spectabilis, n. sp. Pl. XILL., figs. 80, 80 6, and 80¢. Form nearly ~ 
rectangular, broad, with rounded angles; occasionally sub-elliptic. Length from 
0-003" to 0°0047"; breadth from 0-002" to 0:0025’. The inner curve lines bend in- 
wards from the outer margin very nearly to the inner margin of the valve, divid- 
ing the valve into a middle outer compartment, and two terminal inner ones. The 
detached valve has prominent obtuse rostra or beaks, not seen in the entire form. 
Outer compartment transversely striated, the striation being very coarse; inner 
compartments marked with radiate strize, which are much finer. Aspect of the 
whole form soft and indistinct, so that in general only the marginal ends of the 
strie in the outer compartments are easily seen. these strize being thicker at that 
end, and the frustule very convex. Even at the margin they are not sharp but 
softened. Strize in the outer compartment 14 to 16 in 0-001": in the inner ones, 
26 in 0-001", and very obscure. As in the last species, and indeed in many Am- 
