22 
the forms belonging to other genera, and present them to 
your notice in connected groups. 
Amphiprora rimosa,n.s., P\. III, fig. 1.—Valve constricted; 
length ‘0070, greatest breadth :0035, breadth at the constric- 
tion ‘0026. ‘The central line consists of two distinct portions ; 
one, starting from the left margin at the middle point, passes 
inwards towards the centre, turning thence at right angles; 
gradually narrowing, it proceeds towards the apex ; at a point 
about three fifths of its length, measuring from the centre, it 
throws off a branch to the right at right angles to its main 
course, thence it verges slightly to the left and at a short 
distance throws off another branch shorter than the former, 
and in an opposite direction; then turning, it pursues a 
course in a line parallel to its original direction towards the 
apex, at a little distance from which it divaricates into two 
branches of unequal length, the shorter towards the right 
and the longer towards the left, both ending in a sharp point. 
The same description applies to the course of the other por- 
tion of the median line, starting from the right margin and 
running towards the other apex, except that the longer and 
shorter ramifications are alternate to those in the opposite 
lobe of the valve. The striz are very fine, linear, partly dis- 
posed in nearly parallel curves around the extreme points of 
the several ramifications of the median line, and partly 
arranged in straight lines parallel to each other. The margin 
is adorned with a single row of large moniliform puncta. 
Several efforts were made to obtain different aspects of 
this form, but to no purpose, at the slightest touch of the 
bristle the valve being reduced to fragments. 
Amphiprora Nitzschia, n. s., fig. 2.—Length +0067, 
breadth in front view 0013; valve slightly constricted on 
side view; ends produced and narrow, perfectly pellucid, 
the keel or median line presenting the appearances of a rope, 
broad and running to the apices. On first inspection this 
form was supposed to belong to the genus Nitzschia, but on 
turning it over it became obvious that it was an Amphiprora. 
On the front view this species is slightly constricted, without 
any markings, except a few rows of dots at the extremities 
(fig. 2). 
Amphiprora sulcata, n. s., fig. 3.—Valve deeply con- 
stricted, length ‘0054; the lobes formed somewhat like a 
bill-hook, the margin of the inner boundary line jagged, 
each lobe pervaded by four jagged furrow-like bands nearly 
parallel to the outer margin of the valve. These bands are 
easily resolved into short parallel lines, disposed at right 
angles to the length. A small space towards the apex, in- 
