514 PROFESSOR GREGORY ON 
distinguish it from that species, in which the strize are conspicuous and moni- 
liform. 
This species is not unfrequent in the Loch Fine dredging mentioned under 4. 
turgida. It has some resemblance, in the form of the valves, to A. incurva, Greg. 
figured in my first paper on the Glenshira Sand (See Mic. Jour., vol. iii., pl. iv. 
fig. 5). But in A. incurva the striation is conspicuous, not hyaline, and the form 
of the valve is more elongated, and less projecting at the extremities. I am not 
yet acquainted with the entire frustule of A. incurva. 
74. Amphora levis,n. sp. Pl. XIL, figs. 74, 74 6, and 74 ¢. Form of frustule 
rectangular, slightly incurved in the middle, sometimes with the ends rounded, 
but more commonly with nearly square ends. Length from 0:0017" to 0-003"; 
breadth from 0:0007" to 0:0012". Aspect very hyaline. In each valve the inner 
curve line, rising from the inner angle of the valve, and following the margin out- 
wards, bends inwards again in a long graceful curve to the central nodule placed 
just within the ventral margin. The nodule extends asa strong bar across the 
middle of the valve. The outer compartments are transversely striated, but the 
strive are very fine, about 60 in 0-001’, very hyaline, and hardly to be seen with a 
power of 400. 
I have added, in fig. 74 d, the figure of a fine Amphora, which probably be- 
longs to this species. It is remarkable for the fact, that the curve line coincides 
with the outer margin till very near the middle, where it bends inwards to the 
nodule. There are also four longitudinal lines at considerable and equal distances. 
In this specimen, I have not seen the strize as in the others; but believing it to 
be of the same species, I give the figure under the head A. /wvis. 
This species occurs with the last, and is more frequent, though by no means 
abundant. It frequently happens, as in one of the figures, that the valves are in 
apposition ; and as this occurs in long examples, these become proportionally 
narrow. 
75. Amphora exigua,n. sp. Pl. XIIL, fig. 75. Form linear-elliptic, narrow, 
with somewhat obtuse ends. Length from 0°0015" to 0:0022"; greatest breadth 
about 0:00035’. The valves are transversely striated, the strize being strongest 
at the margin. Strize about 28 in 0-001". 
This little form occurs, scattered, both in Lamlash Bay and Loch Fine. In 
size and form it approaches nearest to A. lineata (Pl. XII. fig. 70); but its mark- 
ings are totally different. It has no striking characters, but I cannot refer it to 
the same species with any of the small Amphorw I have here described. 
76. Amphora dubia, n. sp. Pl. XIU, fig. 76. Form of entire frustule oval, 
flattened, or even a little incurved, on the sides. The valves are concave in the 
middle of the ventral margin; so that as they are in apposition, there is a longish 
rhombic opening in the middle, between them. They also diverge a little at the 
apices. Within each valve is a faint line, nearly parallel to the outer margin, 
