Diatomaceous Sand of Glenshira. 
71 
32. Amphora biseriata, n. sp. This is another remarkable 
species of the genus^ which is not at all rare in the deposit. 
It is represented in fig. 32. 
Form of the entire frnstule nearly rectangular^ the corners 
being rounded. Sometimes it is a little elliptical in the 
middle, at others it is a little incurved there. It is often rather 
narrow. Length 0*003 " to 0 0045". The two valves are con- 
nected by a narrow rectangular space. The curve line in each 
valve is not conspicuous, from its projecting so very little 
from the margin in the middle part, and running very near 
the margin all the way to the ends. The striation is coarse, 
transverse; stri«; about 18 inO OOl". In each valve the striae 
are traversed by faint white vertical lines, which are only seen 
when the focus is adjusted to them, and then appear to divide 
the striae into vertical bands of short transverse bars. Some- 
times two such lines are seen on each side. I have named it 
from this peculiarity ; but it is well characterised by its form 
and peculiar striation. 
I do not feel quite sure that I have rightly referred this 
form to Amphora ; but the curve lines certainly exist, and 
there is no other known genus to which it can be referred. 
(285.) 
33. Amphora lineata, n. sp. This form, which is repre- 
sented in fig. 33, varies a good deal, and occurs sometimes 
much longer and narrower, without the recurved ends, and 
with more and stronger vertical lines in the median space. I 
have not had time to obtain figures of the other forms, and 
this one is not so characteristic as others. 
Form oval, sometimes broad, at other times long and 
narrow, nearly linear. Ends recurved, but in some this is 
very slight indeed. Lateral parts distinctly cross striated. 
Median space marked with fine but distinct vertical, or rather 
concentric lines. The form here figured approaches to A. 
salina, Sm., but there are others which have no resemblance 
to that form, and in which the vertical lines are stronger, and 
cover the whole valve, so that no lateral transversely striated 
part can be seen. It is possible that the latter are the true 
A. lineata, and that the form figured may be a form of ^. salina. 
Length from 0 0015" to 0 0025". 
I am inclined to believe that the form I consider as the 
typical A. lineata, not here figured, is the same with a lineate 
Amphora which Dr. Greville has found in the sand from 
Trinidad already mentioned. (286.) 
(In the recent gathering above referred to, I find the form 
which I call A. lineata frequent. I shall give a better figure 
of it on an early occasion.) 
