494 PROFESSOR GREGORY ON 
38. Denticula fulva, n. sp. 41. Meridion (?) marinum, n. sp. 
39, ... Marina, n. sp. (or Gomphonema lineare 2). 
40. Diadesmis (?) Williamsoni= Himanti- 42, Pyxidicula (Dictyopyxis) cruciata, Ehr. 
dium Williamsoni, Sm. 43. Orthosira angulata, n, sp. 
30. Denticula (?) interrupta. PI. X., fig. 30. Form of F.V. nearly rectangular, 
the middle part very slightly convex, and the ends a little expanded. There is 
an apparent interruption of the margin at the middle point on each side, and on 
each side of this opening is a round punctum. Length about 0:0015"; breadth 
about 0:0004’. It occurs in chains of 2, and the two dots of each margin form a 
square with those of the margin of the adjacent frustule. The S.V. is not yet 
known, and the species is only provisionally referred to Denticula. 
This species occurs in Lamlash Bay, but is scarce. 
31. Denticula (?) capitata, n. sp. Pl. X., fig. 31. Form of F.V. generally rec- 
tangular, but with the middle part considerably convex, and the apices expanded 
and rounded. Length about 0°0018”; breadth about 0-0005". Occurs, like the 
last species, in chains of two. S.V. as yet unknown; and it is only doubtfully 
and provisionally referred to Denticula. 
This species occurs only in one of the Loch Fine dredgings, and it is as scarce 
as the preceding. 
32. Denticula (?) ornata, n. sp. Pl. X., fig. 32. Form of F.V. rectangular, but 
somewhat expanded in the middle, and also, after a slight contraction, at the 
apices, which are finally truncate. The margin, at the expansions, is beautifully 
moulded, having a moulding or notch on each side of the middle point.—Occurs in 
chains of two. Length 0:0015” to 00017”; breadth, in the middle, 00005". S.V. 
not yet known, so that the species is only provisionally referred to Denticula. 
This very pretty species occurs both in Lamlash Bay and in Loch Fine, and 
is much less scarce than the two preceding ones. Notwithstanding this, however, 
I have not been able to find the S.V. 
33. Denticula (2) levis, n. sp. Pl. X., Figs. 33, 336, and 33¢. Form of F-.V. 
linear, rectangular, with a small sharp prominence in the middle of each margin, 
and the apices slightly, but sharply, expanded. Occurs in chains of two or three, 
and also solitary. Length from 0-0016” to 0:0027”; breadth 0-0006”. It is 
striated on each side to one-third of the width, indicating that the S8.V. is convex. 
Strizedelicate, but distinct under a high power, about 48 in 0-001”. The general 
aspect is smooth, and the striation is only seen on very careful adjustment. There 
are two terminal nodules visible on the F.V. at each end, which are joined by 
lines bounding the strie. The middle prominence of the margin of the F.V. 
seems to indicate a central nodule on the S.V., which view has not yet been ob- 
served. 
This species is by no means rare in Lamlash Bay, and it occurs also in Loch 
Fine; but I have hitherto been unable to detect the 8.V. I have referred it pro- 
visionally to Denticula, but with many doubts. It is probable that if we had the 
